RJ-45 connectors are cheap, durable, and have a decent mechanism for retaining cables.
Patch cables are cheap as well...
#kicad can't shout at us for abusing them...
So just use them for whatever data you need to get from A to B :P
@trollhacks with the one caveat that like you did here, it is best to not put DC on two wires of a pair so when someone accidentially connects the device to an ethernet port, it doesn't fry the ethernet port's transformer.