It's safer and more convenient to put out software through the Apple mobile devices.
The thing with the iOS devices is that once developers deal with the restrictions imposed by Apple, the consistency/uniformity of the platform pretty much assures that their apps will work. We can't say the same for the Android where you can find won't work on my [insert phone model here] since the update on just about any of the apps worth downloading.
Eventually, someone will come out with an Android counterpart. I just don't expect it to come anytime soon, at least not at the same level as the ones from IK Multimedia, Peavey, Sonoma, and now Line 6 for the iOS.