It may be a pain to only use one connector, but the protocol itself compared to a lot of external busses is a lot nicer. One of the big things ethernet gives is a lot lower latency. The ear is pretty latency-sensitive, with voice latency of 15 milliseconds being a threshold where most people can start noticing. Because of the polling nature of USB, you've got to wait for the bus to ask for data, which means you're going to have at least a couple of milliseconds of latency. Also, because Ethernet is a many-to-many protocol, you can do things like have the synchronization clock on the same connection as data, so you don't need to run a million clock cables along with your data cables.