Most rooms don’t need acoustical treatment.

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. :)

For 41 years, I lived in a 2000 sq ft loft in lower Manhattan. The 1200 square ft open area was the listening space, it had an irregular shape with tin ceilings, 60% of the eastern wall covered with huge windows, a brick wall behind the system, and hardwood for the floors. It was a lively listening room.

Three years ago I moved to a townhouse in Newburgh NY that we gutted and restored. My 500 sq ft office in the attic doubles as a listening area. Dormers on one side, a gable on the other. After 15” of rock wool insulation was put in the ceiling, and 6” in the walls, I covered it up with burlap instead of sheetrock.

Books and LPs line almost every wall.
The sound in my Newburgh home is dramatically improved from my NYC home. Almost like buying a new stereo. And I got this improvement without hiring professionals (although our architect did have a background in acoustical science), just by using basic common sense with regard to what most of us know about how sound works.

Is it perfect? No. But it’s way more than good enough. I’d rather listen to music than worry and tinker.

You do not need any room treatments. At least not while you’re using your headphones.

My room settings are now so good that all my 7 headphones are not on the level of the room on any count...

Then think twice....