I didn't use Gambits because they made me feel lazy and I have a major obsession with micromanaging as much as I can when I play a game. Well I tell a lie; I had Libra on one person's Gambits because the icon indicating that it was active got covered up by the constant buffs I was casting and I didn't want to waste an accessory slot on the Bangle.
That said, I didn't find that not using them made the game any harder. They weren't exactly as essential to beating the game on your first try as, say, Materia or the Junction system. Besides, there wasn't a Gambit to not make your allies stand around like a bunch of lemons when charging their spells while you could run around while doing yours >:| But anyway, this consequently made me scoff a bit when I saw a "No Gambit" challenge video on YouTube some time ago.
Yeah I'm sure this conversation's been had plenty of times before but what did all y'all think of them?