There is no clear meaning behind the Xbox controller buttons, with the exception of “L” and “R” buttons on the shoulders of different versions of the controller. Those reference the right and left side of the controller when holding it. The history of the other buttons stems from controllers predating the Xbox.
It depends on how you use your PlayStation. If on the heavier side, like downloading and playing games, you need 100 GB for the installation of games alone like Call of Duty. Your data usage for game-playing is a different story. Streaming shows uses anywhere between 1 GB and 7 GB an hour, depending on video quality.
Generally, games shouldn’t use up more than 300 MB per hour, and that’s on the heavy side. As a tie-in, Xbox Live isn’t that important if you don’t download anything from it. However, downloading and updating games can quickly take up your data package. For example, Call of Duty: Modern Warfare is about 200 GB.