The only difference here is that in Android you can actually separate the two.
>Although most microG components are far from complete, users are amazed by the results.
What users are amazed by what results? And if you read this carefully, it clearly states its missing swaths of the APIs, so its not 1 to 1 compatible and is very likely out of date in at least one reimplementation, per this [0]:
>This is alpha-grade software and not yet ready for production use. Do not use if you don't know what you're doing.
I don't think this would hold up to being what I'd use as a daily driver. I just want my phone to work not fiddle with troubleshooting weird edge cases for apps I want to use.
I applaud the project, but its hardly a simple as saying 'you can replace it' and that's the last you'll have to think about it.
[0] https://github.com/microg/android_packages_apps_GmsCore/wiki