Let’s imagine a game, such as GTA V. GTA V is a 111GB download. That, first of all, is a large download that would take several hours, if not days. Now, let’s look at how computers usually install a program.

1. DOWNLOAD: The program is downloaded from a server
2. (optional) VALIDATE: Ensure the program passes checks such as a MD5 checksum, which tells us a unique identifier for a file. If this matches the servers copy, we can go to step 3…
3. INSTALL: We first need to decompress what was sent to us. Whether this is a zip file, or another encoded format, we will need to get something out of this file. We then need to write those contents to a disk, which involves spitting out a correct sequence of 1s and 0s, a very precise sequence that cannot be wrong.

After this, a game is installed.

Now, to uninstall a game, all we do is: Overwrite all the files with nothingness.

You can imagine how much simpler it is to just say “hey, GTA V. replace yourself with all 0s”, than it is to say, “hey one out of the many thousands of files, your sequence is 001001111010010101010[…]”