Why does CandyMachine use `cmp_pubkeys` function and not an `Eq` trait?

Question

CandyMachine program has this function, which is used extensively in the program code:

pub fn cmp_pubkeys(a: &Pubkey, b: &Pubkey) -> bool {
    sol_memcmp(a.as_ref(), b.as_ref(), PUBKEY_BYTES) == 0
}

However, I do not see, how this is different from simply using Eq trait.

Answer 1

The sol_memcmp syscall is run as native code which is both faster and cheaper than Eq/PartialEq in eBPF.

You can find the syscall implementation here.