It's dependent on what deck is popular in your area, In general, I think that's a no. Unless your area is filled with nothing but Darkreigon decks then it isn't really enough to warrant them. Sure they're good vs DCE as well but if someone knows you have them they'll just use regular energy and only use DCE selectively/when they know they can get a kill with it. More often than not you'll also find them to be a dead draw and the beauty behind Darkreigon is that almost everything you draw in the deck you don't ever mind seeing.
Also, most of the decks that are good in the format aren't DEPENDENT on special energy to accelerate their gameplan. Zek and RayEels are both fine without it, Empoelon is fine without it, Garchomp is, etc.