Pokemon, a children’s game and thus not worth your time.

That is actually untrue. You can pick what the mystery mushroom is when doing level designs without using an amiibo. Simply place the mushroom in the world (not in a block) and then tap the mushroom. You can then select what costume you want it to do and then place it in the blocks desired. It took me a while to…

That would be Nikki of Swapnote fame.

You’re wrong. You can use costumes once you unlock them via 100 Mario challenge. Many of the costumes don’t have a corresponding Amiibo.

I thought I saw a video where they were able to choose a specific costume without using the Amiibo, just by tapping on the icon. I might be wrong, though.