Exactly what I've observed in practice because most devs have no background in writing functional code and will complain when asked to do so.
Passing or returning a function seems a foreign concept to many devs. They know how to use lambda expressions, but rarely write code that works this way.
We adopted ErrorOr[0] and have a rule that core code must return ErrorOr<T>. Devs have struggled with this and continue to misunderstand how to use the result type.