Right, but as far as I can tell, that handling option also blocks the IP address, which I would prefer to avoid.
Spammers do often use free email addresses, but they’re usually from the big providers like Gmail and Microsoft that make it fairly hard to bulk create new addresses, so blocking the email address is a somewhat effective way of preventing the same spammer from returning while completely avoiding false positives, whereas blocking the IP is almost useless for preventing repeat spammers while also having the possibility of blocking other legitimate users with the same IP.