The word "driving" has multiple, partially overlapping meanings. You're using it in a very informal sense to mean "I don't have to touch the controls much". Power to you for using whatever definitions you feel like.
Other people, most importantly your local driving laws, use driving as a technical term to refer to tasks done by the entity that's ultimately responsible for the safety of the entire system. The human remains the driver in this definition, even if they've engaged FSD. They are not in a Waymo. If you're interested in specific technical verbiage, you should look at SAE J3016 (the infamous "levels" standard), which many vehicle codes incorporate.
One of the critical differences between your informal definition is whether you can stop paying attention to the road and remain safe. With your definition, it's possible have a system where you're not "driving", but you still have a responsibility to react instantaneously to dangerous road events after hours of of inaction. Very few humans can reliably do that. It's not a great way to communicate the responsibilities people have in a safety-critical task they do every day.