The only solid reason I can think carry anything on a USB stick is if you’re going to be in an area without Internet. If you’re in an IT role where you’re interacting with end-user machines all the time, then the answer would obviously be some sort of live environment to troubleshoot or fix issues. In that case, load a Ventoy partition with a few different images, and and be done with it I guess.
If you’re thinking like a Prepper or whatever, keep a copy of Wikipedia, and some survival books maybe? Maps? That’s all I can think of. If you’re going this far, better carry a backpack with portable solar panels, a large battery, and a lifejacket. None of this matters when you don’t have food and water though, so…