[yc12340]

Judging from reviews of hardware keyboard-video-mouse switches, they tend to work MUCH worse than Looking Glass. All modern GPU connectors are digital, so those KVM switches have to include a mini-gpu (usually a costly and buggy one). Also they end up re-implementing a complete HID support, because otherwise switching USB devices between hubs takes forever.

In nutshell, KVMs aren't worth their money because they have to re-implementing a lot of hardware already found in your PC.