I don't use Google Drive on any of those platforms (that I'm aware of).

Meanwhile, Picasa integration was strong enough that it took years for me to figure out how to get rid of the screenshots I used on my blog 6 years ago out of the Photos app on my phone. But I wouldn't bet on Picasa being around for the long term.

Basically, I can easily see Google pivoting away from Drive being a sync client and towards some kind of always-online thing with a light local cache.