I work for an ISP in Switzerland. If you download a game you use 1Gbit/s+ for a few minutes instead of an hour or two. The average bandwidth used stays the same.
Both don't require a lot of bandwidth and you have caches for their content.
You can buy additional data if you've used your included data. That's basically the same.
Paying for bandwidth used is exactly what I am talking about. In less developed places, 1Gbit/s is simply unavailable and usage is capped. There is no economic incentive to build better infrastructure for applications that do require a lot of bandwidth (e.g., Netflix).
