Well, there’s more to the story if you read the whole article you linked to, although I think they drew some wrong conclusions in that article.
Yes, but today port 465 it’s used specifically for submission over TLS, i.e. for email clients sending email through a mail server, whereas when it was first introduced it was meant to be the encrypted version of port 25 which was impractical, so it never gained widespread adoption and was eventually deprecated for that usecase.
For more deatils see my post in the following thread: Occasional downtime (connection refused on 465) - #6 by miabuser