Well think of what would've happened if he'd been stuck in the time loop with the wrist bands! He would've read every book on the base, including Carter's thousand-page tome on wormhole physics. He'd be fluent in Goa'uld, Ancient, Latin, Egyptian, and about twenty other languages. He wouldn't be O'Neill anymore!
I liked the look he gave Carter at the end when she asked if he'd taken advantage of the opportunity - letting the implication that "for a hundred loops, all we did was shag each other, but we won't talk about that," hang in the air.