People, by and large, are stupid. I'm sorry, but we are, and once we reach a certain age, we tend to get set enough in our ways that familiarizing ourselves with new and unintuitive technology just isn't high on our to-do-list, particularly on a vacation. Most folks do not want to spend their vacations taking a virtual IQ test which requires them to memorize and retain new information: they want to relax. My husband and I may have a relatively easy time figuring out how to scan a Magic Band, but I can guarantee that my 5-year-old and my 70-year-old father won't.
I think WDW vastly underestimated how convenient is was to have a printed Fastpass which one can hold in their hand and consult to find out the name of the associated attraction, the return window, and the "rules." Now, guests either have to write down all of their FP+ information (defeating the purpose of not having paper FPs, since they still have to dig around in their pocket for a piece of paper on a constant basis), spend more time with their nose buried in their Smartphone, dash off to a kiosk to pull up the information, or wander around clueless, waving their MagicBand at anything that will stand still. It would be better if the MagicBand had some sort of digital display that would list your FP+ and ADRs for you, for the day. That would actually be helpful.