Most rooms don’t need acoustical treatment.

Why?  Because acoustical treatments presented are in virtually empty rooms. Unrealistic.

my rooms have furniture and clutter.  These rooms don’t really have a need for treatment.  It’s snake oil, voodoo science.  
So why is accoustical panels gonna help?  No one can answer this, most have no clue.
As someone always looking to optimize the sound of their system, I had been reading about the virtues of acoustic treatments and the mention of GIK acoustics several times on the 'gon.

A fellow member friend got some treatments from them that were acceptable to his fiancee and he said it improved the sound some. He said he wanted to do more, but wasn't allowed.

I followed suit and spoke with a very nice, honest guy from GIK, sent him pictures of my room and he told me what it would take to optimize the acoustics of the room given the large open, multi purpose, multi listening positions, unique layout with all the openings. I am not having problems, just always looking to improve when it is worth it.

Net net, I was willing to get a few things and he told me that unless I wanted to get a much more significant number of bass traps that would heavily change the look of the room (and my marital status) it wasn't worth it for me to make the couple additions I was planning on.

I appreciated his refreshing honesty, and if you have the commitment, I would recommend using them. I think any room can benefit from them. Whether the improvement is worth it is up to you. They are a proven science, but I think more appropriate for a recording studio, theater, concert hall or dedicated listening room. And especially for stereo stores or special setups at audio trade shows. That's what their web site focuses on. They are pros.
Not snake oil, but many people buy stuff that they may not need, blind and expect miracles.

The only way to really assess a listening room is to have someone with the gear and software they need come and test the room, preferably with all the furniture in it that you want already.

I lucked out - I had an arched false ceiling already, which solved some of the issues I might have had, and a live wall (glass doors) that we solved with some heavy acoustic curtains.

I could easily have spent many times as much on supposed 'improvements' if I hadn't actually had the room tested

My advice is to pay the money for testing and see whether you have any issues - many can be addressed relatively cheaply.  There is probably a home theatre business near you that can do it, (though they'd rarely be called out for pure audio).
I agree with the OP.
You do not need any room treatments. At least not while you’re using your headphones.
jumia...Suspect this a "plant" to rile up the Forum.  :)

Recently, in my little studio, I’ve upgraded monitor loudspeakers which sit atop a pair of sealed subwoofers, a well-known, proven tube amplifier, and a pro-gear DAC, serving double-duty as an active crossover. Twenty years of disciplined attention has been given to dedicated power sources, outlets, plugs, wire, isolation (surfaces and under the hood,) placement and room tuning to this studio.   This from Dynaudio's website (oh, btw, my monitors are not Dyns):  "The acoustician knows the problem but can’t imagine the solution, so he doesn’t ask the DSP engineer.” 
My Tech is BOTH a 40+ year acoustician AND DSP engineer.  Conversations after recent DSP work following upgrades to monitors and  tube amplification:  

“I'm listening to lots of tunes, attempting to find new verbiage to describe this new presentation and experience. Late last night, I scratched a note to myself, "gradations of dynamic nuance." Now, how do I convey its meaning? This is forcing me to redefine the same language with new insights. I have told chums that I have found some systems TOO dynamic for my liking, often powerful amps with horns, for example. As in zero to 110 decibels in a nanosecond.

This newer discovery certainly has to do with speed, however, more the timing of isolated events within the presentation...arrival times differing on the fly. Imagine an old-fashioned view master slide image enabling you to see the velocity of sounds individually radiating out from specific instruments in time and space as in real life, in all directions. Outdoors, for example, on a busy city street...the ability to identify the source creating the sound, its location, distance, and finally, whether it is still or moving. I don't know of ANY testing instruments that can possibly quantify the experience compared to our ability to listen. Our musical truth. The speed of the dynamics allows individual instrumental and vocal sounds to splay horizontally and vertically in a continuum, as in real life.”  And, another:

“This is quite a trip. Last night I pulled out some old audio war-horse favorites such as the self-titled, ‘Joan Armatrading.’ I flat wore that vinyl album out, however, new stuff is being extracted by the DSP red book on TIDAL. I'm guessing room nodes and obstructions swallow up certain frequencies, obscuring or at least reducing the emphasis of sounds and overall portrayal in the mix. It is almost dizzying to now hear the entirety with a system this capable of stage, depth and imaging. Your extensive work done in the bass region has really adjusted the perception from listening to monitors with subs to a more full-range presentation from row 5 or 6, and more appropriate size. People talk about hearing stuff they hadn't heard before. I'm thinking it's more the changes of emphasis on specific frequencies that draws out a conductor's treatment, for example, with a full orchestra, exposing the intent.”  

In closing, in my opinion, here lies the future of audio. DSP needs to be done with great expertise.  1/100dB changes are possible.  DSP supplements great systems, challenging our older mindsets of anything added to the sound chain, a negative.  

Star  Trek Holodec next!  More Peace, Pin  (2nd Pfizer tomorrow, wife's 1st..onwards, Audio Soldiers!)

Yeah, nothing really matters except just keeping on buying newer, more expensive gear to impress your friends. Don’t worry about cables or the AC mains either. 
And don’t be confused because some of the greatest studios and music halls in history utilized scientific processes together with some very brilliant craftsmanship to create a believable soundstage. It’s all an illusion. 
Well, that’s unless you care about your listening space reproducing beautiful realistic music. :)