I mean with the devs saying this :
"
Julia Lichtblau: When we first switched over to Unreal [5], we turned Nanite on everything we could. I think 5.0 wasn't [compatible with] foliage, that came a bit later,
but as soon as we were able to have Nanite foliage we turned it on.
Then we started to pull back from that and [asked] "does this really need to be Nanite?" We were encountering some assets that [were problematic due to] their construction and the way that the UV shells were set up, so we had to rework some of those assets to make it workable with Nanite
or change it up entirely and go back to the traditional method. We couldn't use [Nanite] for things that would move, like flags. We really threw everything into the Nanite bucket, to learn from it. Now we've been able to build a huge Confluence [corporate wiki] page on how Nanite should be handled going forward."
Doesn't scream they went full in nanite foliage, on the contrary. That's why devs have avoided nanite foliage even if it dates back to 5.1
Foliage that does not move is required.. what's the point? Oh but no pop-in.. I don't know. Is this really worth discussing?
Even Epic encountered a ton of problems and this works almost only for Fortnite in older UE versions because they had huge R&D to determine the performances by trial and error and what works what doesn't and their art style can fit into that very narrow verts count.