Those are potentially valid points against immediate possible inclusion with JoiPlay (potentially less developed and no specific testing/porting for Android). Both are at least partial supposition though. The first part of the response presupposes JRGSS is limitedly targeted at RGSS3 (meaning untested with no or poor support of RGSS1 and RGSS2) without knowing or investigation. In a similar vane, the second part also is without knowledge as many Java apps just work on Android but also many with complex features do not (as they might rely on something platform-specific which needs to be ported, etc.).
My original question was in wondering why someone did not do an Android port of JRGSS vs. the already existing mkxp-android, which seems like it was more complex than porting a Java app (choosing to port mkxp to mkxp-android seems like more work than potentially porting JRGSS to Android; that said, I reallize it is already done). It was not why this was not used in JoiPlay now. I well realized it was not ported (or at least well tested) for Android and wondered why not. Perhaps this thread was not the appropriate place to air such a comment but in reading and thinking about JoiPlay and Android after just having learned of JRGSS made me wonder and I thought some developer might find a similar interest in such a comment. I did not mean to waste anyone's time and I apologize if I did (it was more of an only semirelated offhanded comment and not a questioned that needed to be fielded to the JoiPlay developer).