Its entire purpose is an optimization. You have an expensive operation. A bloom filter can tell you that you definitely don’t need to do that operation. So rather than wasting a lot of time unnecessarily doing that operation, you get the cheap Bloom filter Che most of the time and only occasionally have the false positive where you do the expensive thing when it turns out you didn’t need to. That as far as I am aware of is the only use case for a bloom filter. That said, I have used it for that purpose effectively several times in my career.