You actually can currently read some journal posts under the “News” tab of the “Activity” section, but only from the iNat blog and from the journals of projects you follow. Some folks on iNat write pretty great journal entries in their own journals, so it might be cool to see that content under “News” too. I’m less convinced anyone wants to write journal posts in the app, but maybe?
I use the iphone app and would definitely write journal posts there (once I actually start writing them at all, which I intend to). It would be a productive use of my time in waiting rooms and if I had an android my desire to do so would be the same. I don’t see iphone app mentioned much but I would do all sorts of activities with it if I could.