If your worried about it somehow popping open you can keep it locked with either one of the wire expanding hose clamps or fumoto sells a clip that does the same thing.
As one person mentioned, they were concerned that the drain plug location posed a possible hazard for road debris breaking it off. If that is the case, IMHO that's the only valid reason to not use it. I have seen some drain pans where I would be concerned.
And they sure let you keep your hands cleaner, engine bay cleaner, and less splash etc.