I seriously doubt anyone is going to create Hollywood CGI effects on a phone or tablet.And? Photo editors and video editors and music editors and accountants and engineers and data analysts and IT professionals and project managers and animators and call centre employees are all "task oriented" employees as well.
Just because a given person uses a computer for only a small set of tasks doesn't mean the computer itself wasn't designed and isn't marketed to be used for all of those tasks.
The two examples you gave initially use a tablet or phone because they tailor the interface to the task on those devices. Collect or check data. Easier than carting a laptop around.
I am sitting here answering you on my iMac because it lets me see more posts and type on a real keyboard.
I can do it on a phone but this is much easier.
I can read iMessages on my iMac as well. But I dont.
Different tasks just work better on some devices.
Perhaps go read some UX guidelines (Norman Neilsen Group do awesome work on screen stuff for many many years).