Selective time control, so you can pause, rewind, fast forward things independently. Now you've added immortality into the mix.

• Starting to feel the effects of aging? Just rewind yourself while leaving the rest of the universe in place.
• Got injured or diseased somehow? Just rewind yourself to before that happened and try again. Or, if it's inevitable, just keep rewinding over and over again to enjoy your good health before that happens.
• Always keep your perceptions a few minutes ahead of your body/brain. That way, you can never be hurt or killed by surprise -- you'll always see it coming a few minutes ahead of time, and you can either pause or rewind time in order to avoid it.
• You can keep any loved ones immortal as well, if you choose. Just rewind them to reverse it if they ever age or get injured or even die.

Beyond immortality, it also provides you with other incredibly powerful (and perhaps terrifying) abilities:

• You can, of course, become incredibly wealthy if you choose. Lottery numbers are your playground. Perfectly timed investment choices are trivial. You can accrue decades' worth of compound interest in seconds. (Do be careful, though. You could probably wreck the global economy if you take this too far.) Robbing banks is so beneath you. How much cash does a typical bank have on hand, anyway? A measly few hundred thousand? You could easily make millions, billions of clean, legit dollars in the blink of an eye. Forget robbing the bank, you could easily own the bank.

• From an outside perspective, you never seem to need to sleep. And you can definitely never be caught sleeping and vulnerable. You just need to pause time around you whenever you want to take a nap, then resume time when you wake up.

• It unlocks true 'time travel' -- by pausing yourself and moving the universe forward or backward around you, you can travel freely to the past or the future. And not just yourself, either. You could easily take objects or people with you if you wanted.

• By extending the 'keep your perceptions a few minutes ahead' strategy, you can gain limited clairvoyance -- always knowing what's going to happen in the future. At least, what's going to happen to and around you in the future.

• You can now 'teleport' to any location that you could otherwise get to. Just pause the universe around you while you go there, and resume the universe after arriving. Alternately, you could just slow the rest of the universe instead of pausing it entirely, and now you can cosplay as a super-speedster who can move arbitrarily fast.

• In the (unlikely) event that you actually need to fight someone instead of just using time shenanigans to avoid the fight, you could go back in time and either prevent what made them mad at you in the first place, or kill them while they were young and vulnerable ... or sterilize their grandfather, so they never existed in the first place.

• If you want to fight someone without messing up the continuity of the universe and potentially creating huge butterfly effects, you can just fast-forward or rewind them specifically. Rewind them until they're a fetus. Fast-forward them until they're a dusty skeleton. Really horrify your enemies by doing that half-and-half -- age regress their top half while accelerated-aging their bottom half. Or just pause them indefinitely and leave them as a helpless statue. You could even troll them by slowing them way down -- let them try to fight you while moving at glacial speed. Laugh at them while the bullet they shot at you takes decades to cross the room. (For extra trauma points, you could slow/pause most of their body, while allowing their brain/sensory organs/vital organs to continue at full speed, so they'd be fully aware of how slow they're moving and able to internally agonize about it for a long time.)