Some other states have done similar things (Michigan and maybe Minnesota that I've encountered, if I remember correctly). While a reservation is required, at least in those states one can be made at the moment you arrive at the campground--in those cases with a dedicated phone at the campground, or presumably with the ranger at the kiosk when it's manned, or with one's cell phone.
The main annoyance for me was that I had to figure out what site I might want before having any idea what the campground looked at, usually by talking to someone in a call center who knows where who didn't really have much of a better idea than I did.
