Why the hell would they use liquid nitrogen for that? You can throw a handful of dry ice crumbs in to get the same effect.

Liquid nitrogen is a pain in the ass to transport and store. You need special vacuum sealed thermoses (a little more expensive than your overpriced yeti tumbler) and it will boil away in a few days regardless so you need to have it topped up. Plus, it is far colder than dry ice, so accidents are more of a thing.

Dry ice can be kept in a cheap cooler and costs like $10/lb.