I wonder about the fact that the most followed person @jerrybanfield is using the esteem app so late.Don't know the reasons.I have joined steemit 5 days ago and have used desktop site always.Today itself I started using esteem app on android and I find the coincidence of your post and my usage of the app on same day, much interesting.

1. You have mentioned that pin and main key and posting key is used to start posting : I think as android is an open software, It should be more secured.So that is why the app we need to enter more keys.
2. Crashing : Yeah, sometimes it depends on the phone and sometimes on the app/network.That could be neglectable as we may get updates in the future.
3. Scheduling a post: This is what made me to try the app today.And this feature should also be implemented on the desktop site.

Overall good post and would like to hear a reply from you.