Why is Minecraft such a popular video game?

As a former-minecraft player, I think it has to do with its diversity.
There are so many different things you can do( minigames, mods, etc)

It's very flexible and the sandbox possibility of it goes beyond the actual game code. Also, it's easy to learn how to code it.

Because people like killing time making things and foraging for things in a sandbox world.
Anyone can play. No age restrictions. It can be done solo or on multiplayer.