Not every place in Disney Springs accepts Disney Giftcards nor can you use your MB everywhere. Both are accepted at all of the Disney owned and operated places, but there are many shops and several restaurants that are not owned or operated by Disney. Those locations generally are not connected to Disney's computer systems and thus cannot accept giftcards or bands as payment.
Some of the non-Disney places have chosen to pay a fee to Disney to gain access to one or both of those payment systems, but it's not the norm. You need to ask at each location. As an example, the Vera Bradley store will take Disney Giftcards, but can't charge via your MB. And use of the giftcard requires the store to use a secondary register, separate from their normal ones.
More places will take giftcards than let you charge via your magic band.
Steve