Considering many games make use of cloud computing for online play and similar functions, they probably make up a pretty goot bit of global cloud compute capacity. Likely quite a lot less than the big AI players, but not an insignificant amount.
Yes but it adds up when you consider that just on Steam alone there are 200 million monthly active users.
Today physical discs are rapidly becoming a niche that newer consoles just won't have. PC games are almost never sold physically anymore.