It's the total over the life time of an app.
In 2017, Google Play Services was the first app to reach 5 billion downloads.
The important point from the article is:
If you're not familiar with how the Play Store works, it's important to note that Play Services hasn't actually been manually downloaded that many times. When someone logs into an Android ...
When you activate the fingerprint authentication for any third party app what it does is that it asks your Android system to initialize the fingerprint hardware which checks for your fingerprint. And if it matches it passes that information back to the system and then to the app. The only information that the app gets is that the scan was successsful. You ...
My phone's Google Play app auto-updates around 1:30 a.m. daily (phone is never plugged in at that time), so there is definitely no connection of update with phone plugged in.
Phone must have WiFi on (selected in Google Play settings) for update.