The advantage of subs is that they can go deeper than just about any main speaker, and that they can be located for best result, and that is mostly not where you get the best result from your main speakers. The bad news is that integrating them with the main speakers involves some work/measurement, although in my experience this is not that hard. The other bad news is that you have to deal with room modes, particularly in smaller rooms. You have to do that with main speakers as well, but a bit less so since those do not normally go as low.
In my experience introducing some form of dsp room eq is inevitable, unless you use small main speakers in a relatively large room. The bad news is that most people already have their electronics, and including room eq into the chain is not necessarily cheap or easy. However, it certainly is far more useful than worrying about the sonic signature of amplifiers or cables. It is quite sad that no AVR is sold without subwoofer connectivity and some room eq, but that stereo electronics rarely have anything, or even easy connections for it.
In my experience introducing some form of dsp room eq is inevitable, unless you use small main speakers in a relatively large room. The bad news is that most people already have their electronics, and including room eq into the chain is not necessarily cheap or easy. However, it certainly is far more useful than worrying about the sonic signature of amplifiers or cables. It is quite sad that no AVR is sold without subwoofer connectivity and some room eq, but that stereo electronics rarely have anything, or even easy connections for it.