Since .NET has a garbage collector why do we need finalizers/destructors/dispose-pattern?

Question

If I understand correctly the .net runtime will always clean up after me. So if I create new objects and I stop referencing them in my code, the runtime will clean up those

Answer 1

Mainly for non-managed code, and interaction with non-managed code. "Pure" managed code should never need a finalizer. Disposable on the other hand is just a handy pattern to force something to be released when you are done with it.