So instead of an HTTP syncronous POST request, you want to trade it for a brittle implementation of a to-be-implemented-standard that requires the sending email

So instead of an HTTP syncronous POST request, you want to trade it for a brittle implementation of a to-be-implemented-standard that requires the sending email client to be on point? And that I will wait while my outgoing email server isn't delayed? And what if I use my ISP provided email, and move? Am I just locked out of accounts? I appreciate the thought process of rethinking our assumptions. But this is not fruitful - the tradeoffs are trivially obvious and unacceptable failure modes.