This link[0] has an example; so basically almost anything in a game where it has to lookup massive amounts of data (e.g. logs), the example in the article is to quickly check if the user has already seen an item (in a game with thousands of items [e.g because those were pseudo-randomly generated, think RPGs]). But it's easy to think further applications: quickly check if the player already played this chess game before (all pieces where in the same position) to make sure the enemy does something smarter this time (because that time the enemy lost), and such.
[0] https://blog.demofox.org/2015/02/08/estimating-set-membershi...