What I think is that, depending on your users though, they do not understand your backend enough to make proper error reporting.

The "Bad argument" example, they don't know how many different situation triggers the same error, they don't know if what they did before will help you figure out their problem. In short, they don't know enough to be helpful.

I don't have any great solution to this, but putting a middleman who, although can't help you with programming, knows what is helpful and what is not enough to provide useful error reporting to you might solve it.