[friendzis]

You are correct, one of the main purposes for wearing gloves when handling really cold/hot materials is to provide that time cushion to handle the thing or contain accident safely. The question was why gloves are not necessarily a good preventative measure.

For example if you are arc welding and some nasty blob of molten metal drops on your hand, gloves will provide "heat through" time cushion to remove the gloves more or less safely (easily removable layer also helps avoid hot/cold blob sticking to your body), but keeping the gloves on will most likely still result in a burn. There is a hidden danger with cold that cold does not radiate like heat and we have much less intuitive understanding of how cold affects the skin. Sometimes people get frostbitten during winter activities without them noticing that something was too cold for too long.