On mobile, it’s inconvenient to enter many markdown symbols or do things like indent/outdent. Several other markdown-focused apps (eg., iA Writer, Ulysses, TAIO, Bear’s Panda, etc.) have an extra keyboard full of shortcuts like these. Personally, I consider these a usability must for mobile.
We hear you! A mobile keyboard “editing” toolbar is already in development and we are planning to release this in the next major update. Looking forward to sharing this with you soon.