That last sentence (after the dash) is exactly the rationale for this thread.Ahhh Green Knight, yeah that all makes sense in that context and actually that kind of makes me want to play it! Agree completely re: swift conversions etc. ("road to Damascus" and so on).
Might not be the ideal example for this discussion because in those cases I'd expect more description for such a big play in other RPGs, but yeah with Green Knight this sounds like what it's all about - so I suppose this also points to different RPGs and different situations perhaps seeming to warrant different levels of description.
As well as interesting general conjectures like the ones in your post about what motivates GM and so on, we can look at patterns across different sorts of RPGs.
Eg if the penalty for failing a climbing check is falling, that suggests more granularity/detail in description - or at least more of a move-by-move focus - than if the penalty is you don't get to the top in time to do everything you were hoping to do.