GPUs are no good at point multiplication from what I was able to discover on the very limited amount of data on the subject a few months back. Parallelization is not a performance enhancement.


It is about privacy, for the most part. When you send a transaction with an address that is only known to the network as a hash, you must give your public key, or your public key will be derived from the signature. Then the network knows the public key for that address. But as RIPEMD160 is "160 bits of security" vs. the effective 128-bits of security of a 256-bit elliptic curve, it is 32 bits more secure in a sense, but not really against a brute-force attack as it just adds another step of first converting private keys into public keys (a relatively slow operation compared to hashing) then hashing (very fast) to see if it matches the hash. But since a RIPEMD160 hash is not necessarily just a hash of a public key (could be scripts or something else to throw it off, or one of several signature algorithms in the future), the address space being larger does make it somewhat more secure under some circumstances.