Depends on the unit...

Most small units have to be connected to a computer, due to the lack of "wifi" or "network-cable" (which would only have to talk to a router.)

Some of the larger ones, and new ones, have WiFi and/or network-ports, for "hive" style setups.

The BFI ones that are NOT the TH/s models, all require USB connection to a network-connected computer. A mini-itx would suffice. No need to hook it up to a power-hungry gaming rig, when a 20w mini-itx will suffice. It is just using the USB-Serial port as a gateway to the internet.