RustDesk is an alternative to other remote desktop software, JetKVM is an alternative to a built-in IPMI. It could be used as a remote desktop in a pinch, but that's not really the main point.

E.g. you'd use JetKVM-like devices to re-install your OS via emulated drives, remotely control power (including hard reset, not just WoL and software shutdown), change BIOS settings, or troubleshoot a crashing box - all without relying on any specific software/capabilities/behavior of the given box. Meanwhile you'd use remote desktop software when you just want the desktop to present itself remotely.