What's the difference between "Select, then tap Yes, please" and "Add instantly with +" in the dialog?

With Select, then tap "Yes, please", customers choose their gifts and add them all at once with the Yes, please button.

With Add instantly with "+", each gift's + button adds it to the cart right away. The dialog stays open and shows added gifts as already in the cart.

Both styles show the gift product's image and price. Switch between them under Dialog style in How the gift is added in Settings > Cart offer.

How to add in common settings: offer with a dialog