Dont need any markup language on Facebook.
Steemit is very very simple to use, but definitely way too complex for average FB user.
Need to go even lower down the ease of use ladder to pull in FB users.
I've never met anyone under age 65 that cant figure out FB, and 50% of 65+ yr olds can also use FB.
No way steemit is that easy
You don't have to use mark up on Steem.
The only complicated part of Steem that is necessary is the long passwords, which I admit is a hurdle.