The answer to the question whether BRFplus or ABAP programming is to be preferred depends on the individual scenario. For example, the implementation of business logic with ABAP is obviously only suitable for developers who have mastered the programming language.
BRFplus, on the other hand, can also be used without ABAP programming knowledge, because in this case users are supported by graphical interfaces. BRFplus then generates the relevant ABAP code automatically in the background.
Especially in scenarios where rules have to be complex and flexible, BRF+ shows its strengths. For simpler requirements (and if sufficient developer resources are available), however, ABAP programming is often the more effective option.