The only time I’m going to buy nail polish is to use it as the pyrogen for making Estes-like rocket igniters.
Oh, that's a good use for it, but there are other reasons to buy nail polish.
Back when my fumble fingers were less fumbling, I used it regularly when tying flies or building lures; and to coat rod wrappings when replacing a eye.
It also came in handy to waterproof coat whisker-wire electrical solder joints, when things were actually repairable.