Hey @daltongang, that's a good question. I'm just learning about about this as well but since busy is using the Steem blockchain, what you post on busy can also be posted in Steemit.
From first-look, Busy allows you to do a few more things that are important for a lot of people:
- Have multiple draft stories
- Quick post button
- Save posts for later
- View notifications
- Direct message other users
I'm sure there are many other things to learn, this is just what I've observed in my first look. Hope this helps!