Yes it is real work, of course. In all your examples the iPad is being used in a secondary function to support the main task (fixing a train or whatever). iPad is great for these types of work where it can be used for simple reference or information capture tasks.
No I just gave examples of people doing real work who don’t need lots of files.
An outdoor instructor may just need a single file - their map. A train engineer may need a single file - their reference manual. They’re still doing real work!