sorta depends what you're aiminf at but yes, there is an opportunity cost associated with spending time running this gimmick to try at exotics alone versus using them while running strikes that can benefit you otherwise at the same timeSince the buff is consumed after every Ultra kill regardless - for those of us who don't have infinite strange coins, wouldn't it be best to use them for heroic strikes anyways? Considering those guys barf out 2-3 blue/purple engrams on each death it would make sense they have a better drop rate.