The page outright says that it is not a cryptographic hash, but the Hash Quality section doesn't expound on why (except for a minor flaw on short strings for one of the functions). Does anyone know what the expected collision rate for this hash is?

In other words, I don't care if the hash doesn't avalanche perfectly (half changed for one bit of input change; a requirement for cryptographic hashing so changes are "obvious") as long as the collision rate is ~SHA256. Or, if I should care, explanations would be wonderful.