Mostly we use if for caching. That stuff will be recalculated - which will make for a slow app start and force the installation wizard to rerun, but it won't otherwise cause harmful effects for anyone who has the internet.
Users without internet, however, will lose access to their purchased features until they're back on line. At that point, Play Services will renotify the app that they own the feature and it will be recached. (I've just had a panic about subscriptions. But I think that's true even for them.)
Ironically we use a file on iOS because storage was far more flaky. (And also because iTunes wouldn't renotify us of purchases and because on iOS we had to store the level of consumables.)