For example I play War Robots. A 1GB game
That is one very complex and large game. It actually got so complex to the point to where my old device wouldn't even play the game, it would crash before I could even try to join a battle. So I had deleted it from my phone, and haven't played it in over a year.
I downloaded it on my new device, signed into Google play games, and it resynced everything, all of my robots, my progress, absolutely everything was there without any issue at all.
I also play World Of Warships Blitz, a 1.8GB game.
I had played this game despite it's it's it would run pretty smooth, with an occasional crash on my old device. But as soon as I logged into Google play games it pops up a thing saying other profile detected, I press whatever to load it, and everything comes back... All my ships absolutely everything.
That's the way games should be, if you use Google play games to save all of your purchases and progress, as soon as u sign in to Google play games on another device once you open the game up it should offer to restore everything.
I honestly thought this game did, since it says you can play the exact same game, with the same progress and purchases and everything across multiple devices. But it seems that is not true.
Even though the game knows I have made these purchases by popping up a notification asking me if I want to restore purchases, but then when I press restore it always says "successfully restored 0 purchases"
I can close the in game store, open again same thing over and over and bother ever gets restored.
So I guess the only real way to play the same game on multiple devices, so that if your playing on your tablet and it dies, you can pick up your phone and keep going, is if they link your game to multiple player Identification numbers, which is just a dumb design. IMHO