I've been thinking about getting a standing desk, but I don't understand how they are any better than a normal one. Sure, it's much better for the back, but are

I've been thinking about getting a standing desk, but I don't understand how they are any better than a normal one. Sure, it's much better for the back, but aren't they also really bad for the wrists and arms? Most standing desks I've seen are really thin, with no place to rest the arms while moving the mouse and typing.