Totally... different services provide different ways to have multiple addresseses. The article already mentions one (plus addressing), but there are also others (like FastMail's subdomain addressing)[1]. And many people have catchall or misspelling addresses on their own domain.

That said, I dislike Gmail's "the dots don't matter" since it really screws up calendar invitation handling, because calendars don't handle aliases well.

[1] https://www.fastmail.com/help/receive/addressing.html