That "first-class citizen" idea involves hiding information. You don't have to worry about the details of what it means to hold a function in your hands; you get to just pass it around and work at a higher level of abstraction.

Abstractions which hide information are often good when that information is irrelevant, and in programming you usually have people working together to try to create a better program, so the technique is only applied when somebody thinks it's beneficial.

In legal and financial spaces, however, the incentive for misconduct is high. Rather than abstract away irrelevant details to create a better product, all the dirty laundry is hidden so that the fancy, glittery bits are all their marks see.