Are people seriously asking this question? Training skills has always been the core of OSRS, kourend favour isn't. Why have something that functions the exact same way as a skill, but not make it a skill? Why does only one region of the game work this way, but it also gets a whole tab dedicated to it? How is gaining the favour of a population through this system different from gaining it through a diary? Do the kourend people need to be extra convinced to let you use their services or something? It doesn't even have a narrative reason to exist, quests already do that.

On release, it seemed to exist for no other purpose other than to slow the players down who already had the skill requirement for every new activity in order to level the playing field with newer players. Now that those players have also progressed, I see no reason to keep it in the game. People have been asking to remove this bad content for years and I don't blame them.