Someone stole my iphone and turned it off. Can they do anything with it?

I was at a festival and someone swiped my phone and immediately turned it off so I can't locate it with find my phone. I switched it to lost mode and it hasn't been turned on in 2 days… Is there anything the thief can do with my phone or is there anything I need to worry about? And is their any way they can break into the phone or even use it? Just not sure why someone would go around stealing phones with zero benefit besides maybe selling it for parts.

If it's locked then I don't think so

If you have a passcode on it there's no way they can get into it unless they restore it which will delete absolutely everything on the phone. Nobody can get into a locked iPhone even apple will refuse to do it for you.

Most likely, no.

The only way it can't be tracked down is if the battery has been removed. Once a battery goes in, you should be able to pin the location.
Even if the battery is dead, the most recent location can be tracked.
Because you are the victim of a crime, contact local law enforcement.
If it's locked, it's useless to the thief. Except as a GPS locator for his arrest.

They could reset it but it wouldn't help for them to get to use it. Depending on their know how they may not even get that far. You have to disable Find My iPhone to be able to reset an iPhone.

Even if they did manage to do that they still couldn't use it because of Activation Lock which would require your Apple ID & password.

So pretty much the only things they could do would be to try to sell it off to someone who may not be aware of its status or sell it for parts.

Report it to cops & the maker of the ph.
the dipwad will have to turn it on, when he does, bang, they get his location.

They can be shipped to S.America. They can reboot them or what ever there.

The thief has two options, chop it up and sell it as parts or ship it overseas where even if you can track it the cost of recovery would be far too costly.

Ouch