they are temporary luggage locks, yes, but even the tsa approved locks can be broken.the only point is to know whether your checked bag has been opened for inspection. And I use them to lock bags I leave in the room - deters staff from opening.
Liquids restrictions can put a damper on your efforts to travel carry-on only. But there are tons of solid non-liquid options to help make it easier. Solid perfume, solid shampoo, even solid sunscreen and solid bug repellent are great alternatives to the