Benefits of E85R?

[70SCJ]

I know that E85R is usually made with a higher octane gasoline, but are they any specific benefits other than consistency and a little more octane?
I've seen some locally for sale, but at a hefty price. $5/gal

 

[InvisibleBlade]

I've never heard of an "R" version. This is me just thinking out loud, but I would assume it wouldn't be worth it over regular E85 and it would be more beneficial to step up to E98 instead.