The wires really get in the way, even in a seated context. I often use a Rift S for rally games, and the wire will get caught in the backrest, the wheels, my legs. VR is immersive, so you instantly forget and it's a thick and fragile wire so there's a degree of stress.
Not to mention the trip hazard or ripping it out of the PC while playing room-scale games.
I concur, given hardware constraints that a far more slimmed down unit would have been appealing, and more future-proof, but I believe there's still a requirement for onboard compute for inside-out tracking and handling disconnection events, at some point making it self-sufficient (at the time) was seen as not much more expense.