I see it more as a situation where you know someone is in your house/school/some other place, so you take it off while waiting in case they stumble on you (assuming you have no better weapons nearby and don't want to risk finding one). Personally I would prefer to have a knife or gun nearby but I guess that's not always possible.I'm having trouble imagining an attack that leaves me enough time to remove my belt. I suppose there are some belts that might be easier to remove, and some pants that have large enough belt loops to have no chance of snagging, but I'd expect most folks would end up with their belt half-off about the time they needed it...at best. And anyone who has a wide waist is likely to have to do the rest of their defense without taking a step, as their pants become leg shackles.
Or you happen to have rope on you, then you can use the belt techniques with rope.