Habit vs disease

When is something a habit, and when is something a disease/addiction? What is the difference? Ie. Drinking too much vs alcoholism.

I guess addiction feels like a habit but at a very strong level to me. I’m confused why it is often put into another category–a category that often states person is diseased and they can’t help it. It seems like they may think they can’t help it, but that in reality, they can help it, it is just very hard to do so.

When is life coaching a good approach to disease/addiction and when are other approaches needed instead or in addition to life coaching?