The terminal sessions will persist even if your emulator crashes. Or, if you ssh into a machine you can use multiple terminal sessions from a single connection, and you can disconnect and reconnect to those sessions later.

There's a few other features like a common clipboard of sorts, monitoring a session for silence/activity, but those could all be provided by your emulator.

Keyboard shortcuts for searching and copying text from the scrollback buffer.

Saving your sessions and tabs and restoring them after a reboot.

A consistent experience regardless of which terminal emulator you use.

I use it for running some multiple-hour jobs on a remote VM.

One big one is the multi-user mode