In the case of GTA San Andreas, they pushed an update through steam that removed songs from the radio stations and broke mod support. It's entirely possible that could happen again with GTAV. With San Andreas, I was able to restore the missing tracks from my 1.0 physical copy. If that happens sometime down the road, having a physical copy could theoretically make it easier to revert to version 1.0, but with the social club integration, it's hard to say for sure. Rockstar could potentially force patches that way.