Crimson Longinus
Legend
Conflict, competition, same thing.Conflict between whom? I didn't say anything about conflict. I talked about competing conceptions of the fiction.

But in 5e D&D isn't it open to the GM just to say "OK, although the wall is rather high and sheer, you make it up"? Or to put it another way, the player has no entitlement to insist on a check, as I understand it.
So the GM has to decide how to respond to the player's action declaration - to let it go through "unopposed", or to introduce a new possibility for the fiction (in this case, that the character fails to climb, or falls part way up).
But there still really isn't competing concepts of fiction advocated by different people, and then the rules are used to decide whose vision prevails. Or at least that's not how I see it. Once it has been established that uncertainty exists, rules are called upon to resolve it.
And even though of course in D&D the GM has the final say on anything, in many cases it would be highly unusual for them not to evoke the rules when a situation where it is customary to do so has been reached. For example players generally expect that the combat is resolved via the combat rules.