Below, his tweets have been consolidated in easy-to-read quote format:
“Some more Zelda bits for you: the inventory system evolves. To start with you can only assign items to the X button. At this stage of the game you have lots of items and need to switch often, so the scrolling window of items is needed. Then, when Ravio starts selling you items (as opposed to just renting them), you can tap the touch-screen to ‘quick select’ items.”
So there you have it! Sounds like as you progress through the game, you have more options for how you manage your inventory. It looks like there are going to be a ton of items for you to manage, so a “quick select” option sounds like a life saver!