Right now it’s inferior not-a-laptop with a touchscreen that you can detach and people still buy it.
For the same reason you carry an "inferior" camera, pda, navigation system, cellphone with very short battery life and undersized movie screen: a smartphone does all that okay-ishly. Or why ultrabooks are vastly more popular than gaming laptops. Convenience and form factor trump "inferior" all the time.
Youtube playback would stop everytime another video starts playing somewhere (additional fun when it's just a video ad that actually had no sound in the first place).
SMB file management is still an afterthought, so you end up needing a plex server dealing with all the complexity the iPad can't deal with.
Browsing is the same, outside of the Safari limitation, extensions are few and tab management a pain in general.
For books and magazine it's kinda the same. It works fine for light use. It becomes frustrating if it's something you actually care about.
In the end, I realized I actually care less about visual polish and more about having complete functionalities, at the price of dealing with Windows and managing a computer instead of an appliance.