This is kind of a two-tier question. Disc drives are only so fast and there tends to be a lot of data on the game disc. In addition to that, usually there is a massive update as well. It is kind of an annoying process for sure, this is the one advantage the Nintendo Switch has with its cartridges. When it comes to the updates, it is even worse though. Around Christmas you have tons of other people trying to do the same thing and it bogs the servers down a little.