Tracy, thank you for sharing these five things you like most about Medium. I pretty much agree. I do think the interface is one of the easiest and best I have come across.
I know there has been a lot of talk about Medium not being very transparent in regard to a number of issues, but compared to another writing site I belong to HubPages, Medium is so much better. It isn't perfect but I think they try.
It is also great that we can write about almost anything here, (long or short format) and even poetry is appreciate.
Most of all though, I love the community, and commenting and engaging are encouraged. That make writing worthwhile, whether we make money or not.