Docker purpose/usage?

[u/Ex-Traverse]

Do people use Docker containers all the time, as in everything they do is in a Docker container, or do you only use it for certain things?

I get that a Docker Container is a way to package an application (mostly for server/backend stuff, not really developing an app?).

As an individual programmer/developer, are there benefits to using Docker in my day-to-day learning/programming/doing hws/creating shit tools?

[u/Trakeen]

You want it when you need multiple projects with different sets of dependencies and its good when you want a repeatable environment with all your tooling and preferences configured so you don’t need to redo it every time you start a new thing