Some people want it to sound like it’s supposed to, the way Fleetwood Mac decided or Tom Petty or Lenny Kravitz. ATC enables you to get that, and you cannot get that with passives.
I set up my home theater with the intention of replicating to the degree that is practical what the mixing engineer of a movie or album heard on the soundstage. I exchanged emails with the owner of the Dub Stage and Galaxy Studios. Both were very helpful in advising me on how to treat my room. Wilfred Van Balen from Galaxy Studios and founder of Auro 3D emphasized treating the ceiling and suggested bass traps. I am using a combo of absorption panels and Geofusers from Auralex which are diffusors that can be backfilled with rockwool or polyfil to double as bass traps. Both studios use active monitors and while I am sure they sound much better than my home theater, active speakers gave me the ability to bi-amp each speaker AND have that power go to the driver, not just excess heat. With 13 speakers that is roughly 26 channels of amplification. Even if I had that many amplifiers in a biamp configuration it still wouldn’t be as efficient. If you listen to acoustic music at low to medium levels, no worries. If you listen to concerts and action movies at reference level like I do, totally different animal. Look at these specs:
http://www.cain.cainslair.com/Paradigm%20Reference%20Active%20Series%20Specifications.htm