You buy games on Stadia, those games will be GONE in 3-5 years when they shut that shit down again.
I know, we run the risk with all of our other digital storefronts too. GabeN promised they'd make all the games capable of running offline permanently if they ever take Steam down, but it's just a promise. It's not in writing anywhere. Every other storefront doesn't even have this promise.
But none of them are Google, which is fucking notorious for shutting down everything they don't like anymore. Stadia will undoubtedly be in this list. Purchase at your own peril.