MicroPython is a subset of Python intended for resource-constrained embedded devices, unlike Gravity which is designed to be embedded in applications. This is a significant difference - a while back I considered embedding MicroPython in an application (the Lua/Gravity/Wren scenario), but the Python programmers I discussed this with generally disliked the idea.

It seems those who already know Python want either the whole Python language, or not Python at all. I guess it's easier to learn a whole new language, than to use a language you already know but where some parts are suddenly off-limits?