There is nothing wrong with SMTP ...
... when used properly. Likewise, I still use FTP and telnet and several other protocols that kids today probably don't know exist. They all still have their place, quietly doing the job they were designed to do.
Just don't tell Apple I have a dumb serial terminal attached to a port[0] on an aging iMac, with a nice friendly login prompt displayed for all to see ... They'd probably take me to court on charges of miscegenation or something equally daft.
[0] With a little help from USB, of course.