Well we discussed both of those. The first being probably both cost and the China limitations for maps. But I am leaning more on cost for DJI. Yea Here Maps SUCKS in US and I am sure probably other places as well outside of China.... I am big time spoiled having used iOS DJI 4 apps since they a rent only feature rich compared to the Android versions but their maps DO NOT use Here Maps.
Second part for Epson is a Google licensing issue where Google does not offer the licensing for Glass category. Basically
BT-300 does not fall into the avail licensing categories made avail from Google and because of that they are not able to license the use of the store. They did recommend to use the Amazon Market place if possible as an alternative solution.