Most wheeled luggage has a set of hollow metal bars inside where the retractable towing handle on the top retracts into. They're pretty sturdy, so you loop the pacsafe wire around one or both before locking it and then lock the bag.

Only way to get it out is probably to destroy the luggage or break into the pacsafe itself.

The idea behind it is that the pacsafe itself might be worth preparing for if it's just out in the open tied to something secure. If a thief has no clue it's there and thinks they just have to break the padlock on the luggage itself then it's another layer of defence they're not expecting.

But importantly, it's not really a lot of work from my pov. Again it won't deter a premeditated determined thief with the right tools, but very little will.