As a game designer and forever GM, I've been often faced with a player that responds to an in-game skill/proficiency/ability or otherwise and saying "why would I spent points/time on that? It doesn't do anything for my character."
Many games are rife with worldbuilding disguised as, let's call them character options. For example, a skill related to the history of the game world, or the skill to cook. In some games these are mere window dressing, used to pad out a character's back story. So, again, why would I spend my precious in-game meta currency on something that only tells a story. The truth is, when it comes to making decisions about a character, a player will not prioritize story telling elements if they have no mechanical benefit.
When designing Legends of Lang'Kor, my approach has been to instead design every skill so that it does something for the characters. To be honest though, I didn't know how it would all work at first. I wanted to create a skill-based game, reminiscent of GURPS or Basic Role Playing, so I started with an extensive list of skills (I think there were over 200).
Some were easy to tie to mechanics. Combat skills, those were the easiest, you test them and the result shows whether you hit someone or not. There were other obvious ones: climbing, persuasion, woodcrafting, etc. Any skill where the output was either a certain action (climbing a wall), making something (crafting a wooden table), or getting an NPC to do something (persuading them to let you into town after dark) was easy to tie to the rules. But I had a few that were more abstract, things like architecture, chess, cooking, survival, etc. I had to find a way for the outcome to be more than just "well, you got a good roll on cooking so you made a good meal."
So I thought about what would motivate a player to spend points on cooking, for example. Because if the outcome was simply a scene setting item, no one would spend points on it. Multiple playtesting sessions confirmed this, as no one spent time training these "fluff" skills. Instead of simply taking them out of the game, I decided to try to tie them to game mechanics I already had in place. With cooking, I granted a recovery bonus for adventurers having a warm meal. As in, finding an Inn to sleep in or having someone cook for the party while traveling helped them overcome fatigue. It also had the added perk of lending itself well to the thematic elements of the game.
