Having been to Disney world this past august this is just a more advanced version of the system they currently have in place. The only real difference is you currently use your park pass and buttons (personal event greeting) instead of an wristband. The new thing is pre-booking some ride times which considering the lengthy wait times on some of the more popular rides (2 hours+ some days). Disney constantly tracks ride times, guest flow, guest approval and a whole host of things we would never think of all to improve the quality and safety of the experience to allow you more time in the shops and restaurants where they make the real money. Disney above all is into selling you as many of those trinkets and meals as they can manage. The rides are there to give you a reason to come back.
As for the other issue mentioned (scanning your finger print) it is to prevent people from buying one yearly pass or multi-day pass and renting/selling the use of the pass. Neither of which I can blame them from wanting to prevent as this does cut into there bottom line on ticket sales and skews park numbers.