There is one more 'lie' missing and not included in that writing which only looks email addresses what is are limits of valid destination addresses.
But if used as a senders source address there are even less limits.
For example you can use a null address when sending. That has been used bit less these days than earlier. It's been used ages SMTP delivery status notifications, mail loop prevention and so where intentionally not much sense to expect anyone to reply. And all well known MTA's forward it and email clients handle it very well by disabling reply to that message.
There is however a catch that anyone who thinks he would now start using it when he doesn't want any reply. Ever since IT Service Management (ITSM) and Service Desk software appeared, they have had issues with email coming from sender, because they like to always add received messages email addresses to database, where then someone handling would reply. I've been using only few, Service Now (SN) more lately and before Issue Tracker (IT), both didn't at least about year and half ago know how to handle null sender addresses. Both seemed to just discard or sort some trash bin those emails. With our SN sysadmin didn't find where those went in that system.
But otherwise as a sender works great. And sure it would be great if those ITSM making folks would get this fixed, because when your postmaster, postmaster, etc. and such role-aliases are the quite often handled by ITSM software, there is good chance you don't get some important notifications from systems that rely on that null address sender.
ps. Search Google: smtp and sender address as "" for more info incase needed.