I can understand replying to an email as a method of confirming because:
- You have received the email which includes some unique element.
- The reply will reply to a unique email address for that user / or include a “key” in the email headers / message.
To just accept an email without any “key” (currently a unique URL) generated by the server does not confirm email address ownership.
Emails are still very easily forged!
The outlined method by OP is not one I would back.