It was fun exploring telehack and “visiting” systems where people of worked with decades ago were still logged in... but I still use telnet today to poke at ports, or when I can’t remember curl syntax.
Telnet is made for speaking the telnet protocol. The only reason some people use telnet for other things is that most other protocols have control sequences that happen to have no effect on a telnet connection.
<https://manpages.debian.org/bookworm/inetutils-telnet/inetut...>
From the manual of the old Linux NetKit telnet: “When connecting to ports other than the telnet port, telnet does not attempt telnet protocol negotiations.”