Pro work can be done in iPad. Audio production, photo processing, painting, 3D modeling and what have you.
The only pro thing that is being complained about here is programming but hey most people are not programmers. Don't let the HN echo chamber mislead you...
There is a lot of gotcha outside of the obvious stuff.
For instance iOS's process management model means your program gets suspended if it goes too long in the background. Let's say you want to write an email in fullscreen while exporting your superb 4K movie in the background, tough luck.
Idem if you want to have multiple programs running video content in parrallel (or even look at multiple videos at the same time. Short of using a dedicated app, the default ones won't help you)
The browser situation could get resolved as the EU has pressured Apple to do it, but there is still a lot of things that could get improved to help power users, even outside of our circles.
The only pro thing that is being complained about here is programming but hey most people are not programmers. Don't let the HN echo chamber mislead you...