Yeah these anecdotes are great. One of the ones I found amusing was how the windmills in Perfect Dark were reskinned autoguns/turrets, presumably to implement the movement aspect more easily.
As a result, if you get too close to it with cheats or glitches, the whole windmill will turn and fire at you:
And the Ascend ability from Tears of the Kingdom was a developer tool that got repurpose into an in game ability when they realised it'd make the caves much more convenient/enjoyable to navigate.