the beautiful thing about bloom filters is they let you say "definitely not here" without checking everything. that asymmetry is weirdly powerful for specific problems.
I've seen them save startups real money in caching layers - checking "did we already process this event" before hitting the database. false positives are fine because you just check the database anyway, but true negatives save you thousands of queries.
the trick is recognizing when false positives don't hurt you. most engineers learn about them in theory but never find that practical use case where they're actually the right tool. same with skip lists and a bunch of other algorithms - brilliant for 2% of problems, overkill for the rest.