What you say is often true, but in the case of Discord, at least in my case, you are wrong. My Discord email address is discord@xxx.com, and I am still receiving emails from them.
replyIt happend to me when i created my account in 2025. Within seconds of verifying the address I got a email that my account was band for TOS violation. I than created a seconds account (within minutes from the same IP) only writing "dc" instead of "discord" and that worked. ¯\_(ツ)_/¯
replyApparently they (unlike other entities I've dealt with) did not go back and review all of the existing, valid email addresses in their user database.
replyIt's always an unpleasant surprise when some company terminates a years-old, active and valid account because of a stupid policy change on their part.