I have a bunch of NMT too... but after that my 'wallet' felt too empty so I went grinding them during my vacation. Also to just have something to do in the game, as I find I still like it to kill time but I also need a bit of a sense of 'achievement'.
Right now I try to finish at least the 5 goals that give double points each day.
I still need 2 or 3 fishes, so there's a bit to do. Diving is fun but I find it also a bit slow, plus none of the diving suits really look great on me. The problem you have with not needing miles, is one I have with money... If I want to, I can easily earn a bag of bells a day, and that's more than I can spend especially now Nook's is cycling mostly through items I already have.
What are you spending all the money on?