Absolutely. What I’m talking about is something like Bloodstained, where honestly the upgrades simply meant you now get to proceed to the next linear area in the game, where the area now can use the ability you unlocked, but lots of older areas have no use of it.

An example of a “key” like ability in Hollow Knight is the rocket dash. It’s only ever used to bypass an obstacle you normally wouldn’t be able to cross, but at the other side of the obstacle, you have no more use of that skill. I suppose it can be used in rare instances to travel around the map faster, but only if there’s a straight path.