I'd rather delete/block it than reply/react to it at all. If you react, they know you exist and you are a valid target to re-target repeatedly, resold to other marketers.
Sadly I think it is illegal to sing up these addresses to every service known to you... Otherwise it would be interesting SaaS opportunity. Automatically sing-up spammers to any number of newsletters or contact forms...
When they're paying real money to scam you, wasting their time isn't a terrible idea. Like keeping the Microsoft virus scammers on the phone for an hour while you set up a virtual machine for them to remote into.
Mark as SPAM or Block/Filter or Ignore.