Again, they don't just heal instantly from any old attack
Gunko instantly regenerated the entire upper half of her body when Usopp blew it up in their first encounter pre-flashback.
Maybe it’s because Gunko has the deep deep sea contract, while Qilingham only has the deep sea contract, but even Harald was shown regrowing his arm after Loki took it.
Haki is probably the determinant in how effective attacks on HKs are.
Are we winning again?