Jerry will probably chime in here but I'll provide what I know and suspect...
1. Scott Roberts explained in one of the videos that the database is separate from the app for two reasons... a) to keep the size of the app small which allows them to keep it free in the usual app marketplaces. And b), keeping the app and database separate allows ES to occasionally update the database with no affect on the app and vice versa.
2. I admit that I originally thought that using this app on a phone would be convenient. However, after using the app on various tablets, I can honestly say that a smaller screen size would probably cause more 'fat finger' issues. As it is, people are having some fat finger issues with 8 inch tablets. After using this app myself, I know that there is no way I could ever get my fingers to fluidly use the app on a smaller screen. (And yes, I do have big problems with fat fingers when using any apps on my phone... so my phone only gets turned on when I need to make a call which turns out to be about four times each year.) I'd rather keep using Explore Stars on a tablet in the 8-10" range to avoid any confusion as to whether a problem is an app problem or a fat finger problem. The one possibility for a phone app would be if they could divide the current "Home page" into separate screens so they could make each section large enough to be used on a phone. A swipe-able four page 'Home page' might be possible. Although, I'm still not sure I would not have a fat finger problem. It could potentially be useful for others, however.
Thanks Patrick, always appreciate your opinion.
If the size is what keeps the app free than I'm all for it.
As to the fat-finger issue, I agree with you that the app as it is now is not convenient to be used on a smaller screens.
The user interface of the app can/should be redesigned to adjust to the smaller screens. They could make it a tabbed version where the joystick would be on the first screen, you swipe right and you see the numeric keypad and navigation keys, one more swipe and here is your catalog, and so on...
It may just be the funding that prevents ES from adapting to the smaller screens. App developing/testing cycle is brutal.
For fat fingers there is an inexpensive solution from ES: