Why real SMTP verification instead of just trusting an AI guess

Most lead-gen tools stop at "the AI thinks this is the right email." Locus does one more step: after the AI finds a candidate email, it does an actual MX lookup and SMTP handshake against the mail server, checking whether the mailbox exists, without ever sending anything. Only a confirmed rejection downgrades the AI's answer; an inconclusive result (a slow server, a greylist) leaves it standing.

Curious what people actually do for email verification today, whether it's a separate paid tool, ignoring it entirely, or something else. Happy to go into how the handshake logic works if anyone's curious about the implementation.