[rzerowan]

Id think its for enduser flexibility and convenience. Its more involved to alter DNS records vs just adding a text line to a webpage and hitting that default endpoint as standard. Same way LetsEncrypt allows the easiest setup with the .wellknown endpoint , where a user may not have DNS access beyond the initial A record setup.

[inigyou]

Why is one more involved than the other? DNS is just a text file too. And you might not even have a web server. Why should mail servers be required to also be web servers? And what if the web server for that domain is already a completely separate system, and now you force it to be linked to the email system?