Well, I don't own a Rift, but I assume you can't just walk up to your PC while it's in sleep mode or whatever and without touching it, put a Rift on your head and automatically continue playing a game you had been last playing two days ago (Something that they've promised the "Oculus Go" will be capable of)
If your PC is on and your Rift connected you don't need to touch anything it detects when you put it on and throws you right into the menu we're talking about 5 seconds from it detecting you're putting it on to hitting the menu.
Honestly have massive respect for the Oculus team and their user experience, if I had to boot up Steam every time I used VR it would start to fall into more of a chore.
I definitely see value in stand alone devices for these reasons and for the casual users, but I do also see value in having top end PC power in a tethered device for creatives and serious gaming.
Exactly, the thought of having to move the sensors around for optimal performance (I can't leave the 2 rear sensors with cables on the floor out in the office), and recalibrate each time translates to the Oculus not being used.