Sample conversation:
"So how does your fighter have 18s in Str, Con, Dex and Int?"
"I rolled lucky!"
"You do remember we were all supposed to roll up here today right?"
"My dice got hot at home, I can't help it"
Point buy solves gamer cheating, b/c it's really easy to do the math and see that a point combination is impossible. I used to game w/a friend who would work herself up about playing a very specific character leading into a game. Then she would roll stats and find herself unable to play it. Then she would either make something else, whining the entire time and probably for a few sessions after or she would end up sulking and not playing at all. Yeah, I don't game w/her anymore for several reasons.
Point buy saves me from that too. She can work up exactly the character she wants, within strict limits. There was never any point buy in RIFTS and that certainly produced enough min/maxing to last a lifetime

I can't roll for crap. My Daggermaster Rogue would frequently only need a 4 or better on a charge, sometimes I could hit my target so long as I didn't roll a 1. I miss WAY more than I should. My wife can roll multiple 20s every session and if we actually roll 4d6 drop lowest....she can roll one of those 3 18 characters legit in front of the DM. Meanwhile 2 of us got lucky to have a 16 and only 3 numbers are double digits.
Point buy gives a certain understood level for the game. I tend to min/max, freely admit it. My rolls suck too badly to not pick up every bonus to hit I can finagle.

I have other friends who don't want any single digits and will happily knock down that prime stat a bit and spread the love around, b/c they don't want any low defenses and want to be all around good. Point buy doesn't promote min-maxing, it promotes being able to shape your character more closely to what you want. I actually was pretty against point buy in D&D prior to 4E, but I'm happy with it these days.
Obviously, YMMV.