What does that have to do with use vs. abuse? And are you excluding orally ingested drugs (e.g. LSD) from your claim about "always abuse"?
Because you don't have an abuse with alcohol in moderation and if it takes time to get going, you may never have a problem.
With pot and other drugs, it goes to a whole different area of the brain with it's effects (which you are welcome to go research as I have in the past).
Smoking gets things into the system faster and more effectively because the lungs instantly send it everywhere in the body.
That is one of the reasons there are inhalers...