When would one ditch their weight belt?

So weight belts and integrated weights all have quick release mechanisms so they can be ditched quickly “in an emergency”.

My question is, what kind of emergency is that where one would need to do it?

Other than jumping in the water with 3x more weight than needed, when would that be needed?

I cannot keep thinking that in most situations the danger lies in accidentally ditching the weight rather then not being able to do it. What am I missing?