Parmandur
Book-Friend, he/him
The only possible way that system could not matter is if accept the fact that it is nonbinding. I wholly reject this notion. This is not a feature of the way I play roleplaying games. I cherish the moments when system gets in the way and we all get to experience the story/game together rather than any particular person deciding how things should go. I am broadly suspicious of anyone who claims to be making decisions for the sake of "the story" as if they could know what is best for it because we should all be playing to find out what that is.
For my money the entire purpose of these games is to regularly and routinely get in the way. They introduce to the fiction things that wholly unwelcome, but nonetheless compelling. Bits of fiction that no one at the table would choose, but we are all better for. Stuff that shifts the narrative in completely new directions that all the players, including the GM, need to respond to.
You cannot have real tension or real game play if the rules are nonbinding.
It may not matter to you, but it is deeply important to me.
The outside force of the action resolution is what provides the game energy, along with a judge who can adjudicate the resolution. However, it makes very little difference in fact what dice are being rolled and what process is used for adjudication is applied.
Hogwash.
The people I play with matter, not what math we use when rolling dice. The latter is accidental to the experience, not substantial.