Oh, you have 1 of those for each server, like a normal IP-KVM. So there's a network, a video and a USB cable for each server, plus the server cables.
It should be able to build a device where you use an extra USB for each server plus one network cable for each 4, 8, whatever (if you push it, your entire hack).
To use it, you would SSH into the pi, and use a command to get a server.
The serial interface is quite old, everything tends to be accessible there. But now that you mentioned, I'm not sure you can update the BIOS with it.
So you can do that if you want, you would probably need some USB hubs to accomplish, and probably a logical way to map out your serial connections, but it should be doable.
Or in the case of how I did it, i setup a multi-port KVM, that allowed me to manage x number of devices (with video) from a single unit. In this instance, a serial connection was used from the pi to the actual KVM which allowed me to switch inputs etc, from the gui.
It should be able to build a device where you use an extra USB for each server plus one network cable for each 4, 8, whatever (if you push it, your entire hack).
To use it, you would SSH into the pi, and use a command to get a server.
The serial interface is quite old, everything tends to be accessible there. But now that you mentioned, I'm not sure you can update the BIOS with it.