A distinction without a difference.

If you want to develop an app for more than a miniscule fraction of Android devices, you need Google's blessing.

Not quite.

Somewhere in the range of 25%-30% of Android devices (1-1.3 billion) don't rely on Google services. Mostly Xiaomi, Oppo, and Vivo devices in China, but also in Russia, Indonesia, and Thailand. And all Huawei devices.

Sources: https://commandlinux.com/android/android-global-market-share..., https://support.google.com/android/thread/29434011/answering...