Something that was costing Disney $1-$2 times millions of guests per year is being eliminated.
In it's place is something that will make Disney $3-$4 in profit times times likely at least hundreds of thousands of guests... Actually it'll work out to more than that in profit because the upsell to fancier bands will be easier since there is no default included anymore and of course, the difference in cost to Disney for those other bands is nearly non-existent.
Since they aren't passing any of that savings on to the guests it's pure profit.
As I've mentioned in the past, if they wanted to be consumer friendly, they would set it up so that the default at the time of reservation would be bands being declined but with the ability to select bands and have them still be included in your price.
That way, mom and dad with their iPhones and Apple watches don't need bands and therefore don't waste them but grandparents and young kids still get the benifit of what was included last year in a standard resort stay, if needed without it now becoming a tacked on fee.