I have one of those lying around, but the issue afaik is that the Steam Link kind of takes over the PC that is running the games to stream the system. Hooking up the speaker/controls/VGA of my arcade via a long cable directly to my PC, means Windows sees it as another screen with more devices.
Then I just tell VMWare Workstation that the arcade joystick USB should go directly to the arcade VM, and drag the VM window over to the arcade screen. This means I can use my computer directly as normal (I code in a linux VM on it), while the arcade is running independently. It works really well and lets me use a spare 4ghz core to run Hyperspin+MAME faster than my old arcade PC ever did.
Then I just tell VMWare Workstation that the arcade joystick USB should go directly to the arcade VM, and drag the VM window over to the arcade screen. This means I can use my computer directly as normal (I code in a linux VM on it), while the arcade is running independently. It works really well and lets me use a spare 4ghz core to run Hyperspin+MAME faster than my old arcade PC ever did.