It weird so many young people do most of their work on iPhone, including producing videos, photos, and text. Yet when it comes to iPads most people don't want to touch it for work.
For a generation that has been texting on touchscreen for years, the muscle memory for typing on a phone is pretty well defined. In my experience, typing on a tablet requires different muscle memory and is slower.
If you add a keyboard and stylus, the iPad could be more useful than a phone. But at that point, you're spending a lot of money to improve a device that still has all of the limitations of iOS.