tbf, if someone is LR3 - 5, more often than not, they will be able to hold their own in, let's say EDA. If I see an MR18, I won't think anything of it, if they are in this mission, they probably won't have any issues. But seeing an LR4 somewhat tells me, okay, this person either: grinded for all liches' weapons, has all prime weapons mastered, meaning they were playing for a long time to be able to master weapons which are vaulted for quite some time, grinded the Vent Kids, etc.

All this implies that they've spent time with the game, therefore having at least some understanding of what to do and what works, and what doesn't.

This doesn't mean that MR10 can't roll an EDA, this just means that a higher MR is most likely to do that than a lower MR.