How could you use the ability to stop time, to cheat in a casino?

You could not alter a slot machine outcome if you had the ability to stop time.

But it would be useful in all most other forms of casino gambling as you could see what card(s) the dealer and other players have to know how to bet

Stop time, walk up to some table games, pocket some small denomination chips, return to the exact spot you were in, resume time. Not large denominations because then they might stop using those chips until the thief is caught trying to cash them in.

Or place a large bet in a table game, stop time, fix the deck/dice, resume time.

For the slot machine you'd have to stop time, open up the machine and alter its programming.

You could use it to cheat at craps by changing the position of the dice an instant before they land. And you could do the same with roulette by making the ball land in the right spot.

doesn't that make you an imaginary cheat and a thief? So which poker sites do you play on as I'd er like to give you a game?

I think roulette would be the best bet, although the security camera would wonder how your chips just magically appeared on the winning number... but since they didn't see you put it there, you might get away with it.

Slot machines, no way to do it unless you knew the mechanics of the machine and could rig it.

They all have random number generators in them; time is not a factor.