* having an easy way to connect to all machines in environments where not everything is built the same way and on the same cloud or whatever. A big company can have a ton of teams building stuff across a variety of clouds and DCs. Not to mention those machines could be dynamic, so you need to add discovery. Heck, there might be Windows boxes here and there.

* having audit logs of who run what command on which server when

* extra security features like team management, MFA, etc.

You can do all that (minus audit logging) with SSH, sure, but it takes time and effort by the people who care least ( practitioners) about those things ( security teams). Buying something like Teleport or Wallix or Boundary solves all those problems at once.