I think we both realize that taking 80% less damage every round is the practical equivalent of quintupling your damage output, when it comes to resource management.
Are you imagining a scenario where the whole party is fighting one lone rogue? Or a fight against
only rogues, who all have sufficient room to hide every round? (And can somehow maintain cover, while attacking, however that's supposed to work?) Because that's the only scenario I can imagine where hiding would significantly reduce the damage taken by the rogue's side, and even that would require the party to not take the obvious countermeasures.
In a practical fight, while there are non-hidden targets available, very few attacks will be heading toward a hidden rogue anyway, so hiding doesn't really conserve any resources. And when the rogue is the only one left, everyone just readies their action for when it re-appears, and the fight is pretty much over at that point (probably because the rogue runs away while hidden).
I don't know to what you're referring to here, especially the part in bold. The DMG just says to treat Nimble Escape as +4 to-hit and AC. What formula are you talking about?
The damage calculation, for determining offensive CR - it asks you to add up all damage dealt in a round, which is then modified by your effective attack bonus, but it doesn't differentiate between one chance to apply sneak attack or two chances; it just treats it as a total increase in damage equal to the damage of the off-hand weapon, which might not even shift the offensive CR calculation into the next bracket.
If you hide every round, then you treat Nimble Escape as a +4 bonus to hit when calculating offensive CR (which is significant). If you instead use two-weapon fighting, or a feat that mimics its effect, then you calculate CR as +average weapon damage (which is not significant).
If your goal is to maximize the effective CR of the creature, then hiding every round has a greater impact on calculating both offensive CR and defensive CR than anything else you can do with your bonus action. If your goal is to maximize damage output, because hiding doesn't actually conserve much in the way of resources anyway, then making two attacks is usually preferable to making one attack with advantage.