You shouldn't have a problem with wraps coming off when wet.

I use them for a lot of reasons;

They're easier to see in flight.

They help to find the arrow after the shot.

If the arrow doesn't pass through, its sometimes easier to spot a wrap sticking out of the side of a deer than it is to spot just the deer.

My Blazers adhere better to them than the bare shaft.

The look pretty slick.