You can use spinning for every single bass fishing technique.
Casting, as @roadwarrior suggested, probably handles moving
baits better. Cranks, for instance, can get tiring if thrown all day
on spinning.
As has been said, confidence is what it boils down to.
My own experience has led me to spinning for the majority of all
I throw, and I have one casting reel and two rods to change out
based on what I want to throw.
I set out to go 100% casting, and did quite well doing so. But one
day a light came on while I was on the water with only two casting
rigs. One of them backlashed (and I'm very competent at casting,
BTW). That day it dawned on me that there are certain things
spinning rigs excel at, including windy conditions, straight drops,
etc. Point being, use what you feel competent/confident in, and don't
bow to pressure that you *have* to use x or y in order to be a complete
fisherman. That's just not true.
If @Fish Chris and @SirSnookalot were still around, they'd have some
good spinning advice. And Fish Chris has caught some of the biggest
bass you and I will ever see - on spinning gear.