There were quite a few things that Nicholas Hatter loved to do.
One of them was drinking tea with his good friends, and they always threw the best of tea parties. Then there was the pleasure of asking and making riddles—nobody really got the answers. He was still finding answers for them too. And among those things was his love of making hats. If that wasn't very obvious right now. He was in his very own Hatter's shop for goodness sake, and he was working on some orders that were recently placed.
The Gathering of the Suits was good for business.
He and the rest of the people in the Kingdom of Hearts would benefit from this and especially when some trade agreement occurs between the kingdoms. The King of Hearts would surely do a splendid job during the meeting and bring about more success to the Kingdom. Everybody had been happy when the King had arrived and he also did a very good job at quelling the Queen of Hearts at that.