I think this is a great additional option for those who already own an Apple Watch, and don't see the magic band as a necessity. For me, the magic band was fun to use at first, and I still wear them as a decorative accessory, but would prefer the simplicity of having the functionality streamlined to the watch I'm already wearing daily, and that I use to pay for items in the parks (didn't like using magic bands for payments).
For those who still want magic bands, Disney is not taking them away. You can still use ones you already own, or purchase them to be used around Disney World.
So, at least to me, this is a net positive. The only people who might be losing out are recent first timers, who don't get to experience receiving that magic band package in the mail before your trip, and scanning it to get on the Magical Express at MCO. That was fun.