Of course I use it (or them)...that's what they're for, to get different sounds........otherwise, you'd be compelled to strum or pick at the freaking 12th fret or at the top of the bridge like some kind of banjo player....duh....................not to say that playing up on the neck is a bad thing, hendrix did it often for that "sound", but he didn't do it for chording.......the knobs are the only things that can make chording do what you want...or at least what I want.....
I middle-of-the-road it on the amp tone knobs, though......the main function of an amp is volume, if ya really get down to it....if the instrument doesn't have the tone to begin with, it's hard to fake it................just my opinion...........gibs