Actually, a counter-point: there might be situations where you want an anti-cryptographic hash function - where similar inputs produce generally similar hashes.
It could have some application as a preprocessing step in clustering (if it could be done efficiently).
Those are called fuzzy or locality-sensitive hashes; they’re used a lot in image processing for similarity testing, for example. I don’t consider them to be in the same category as normal hashes, though, because fuzzy hashes have vastly different properties.
It could have some application as a preprocessing step in clustering (if it could be done efficiently).