More for looks.....I like rims with a huge lip....looks sexy in my opinion....But its to much trouble getting a 19x11, I could settle for a 19x10.5.....
Lip size doesnt really matter on width of the rims...it does help but with a 10.5" rim as long as you get the proper offset you can get a pretty deep dish. I've had a 2.5" to a 4" lip on my car before all on either a 10" or a 10.5" rim.