If you are doing this so that your co-workers end up having to do parts of your job ... maybe it's not a good thing.
Heck I wanted to replace a dozen light switches awhile back. Could I do it myself? Sure. Did I pay someone else to do it? Yes.
Instead I hand them a big box of switches.
What point are you trying to make exactly? Paying someone for services has absolutely nothing to do with manipulation or deception.
I don't have to pretend to be an idiot for this transaction to be efficient. Learned helplessness is a manipulation technique used to fudge the numbers when the value gap is very small: by adding the good feeling of helping someone in need to the mark's side, you create an efficiency where none existed.
However, if you hide a feature you have in order to not be solely judged by it, its more difficult. I.e. a prince hiding his lineage or an artist hiding his craft.
A good measure is probably, to ask yourself if the other would feel betrayed if you told the truth.
The given example (going to the bank teller instead of learning to use the ATM) is a weird one because the bank teller is much slower and requires more cognitive load than using the ATM.
I suspect the ATM example was given because the bank teller isn't losing anything by dealing with a customer. It's their job and they're on the clock anyway. In practice, people who use the "stupid by choice" strategy are usually dodging tasks at work or getting other people to do things for them, in which case the other party is actively losing time and energy.
It's manipulative and dishonest, despite the arbitrary (and nonsensical, tbh) example going to a bank teller instead of learning to use an ATM.
"Need" is a pretty amorphous word. He may not have needed pictures to understand the docs at all, but he could be said to have needed pictures to understand the docs in the timeframe he had available. Calling it deceitful feels untrue to me. I would only say it's deceitful if the intended use of the pictures was something other than understanding, like he wanted to steal them for another purpose.