You’re thinking of a desktop KVM for connecting multiple computers to one set of devices. This post is asking about network attached KVMs for providing remote access to virtually a keyboard, monitor, mouse plugged directly into a machine. This allows out of band access to things outside of the operating system - e.g. bios/efi, entering full disk encryption passwords, even pressing power/reset buttons via jumpers to motherboard headers. This type of KVM is equivalent to Lights Out Managers like LOM/DRAC in the server world.