DeletedUser4381
Guest
At this time, yes, Promethium doesn't have a vast use like a number of other resources in the game do. This will not necessarily always be the case though. For example Medals weren't "useful" beyond the Victory Expansions, but you can now use them both in GvG and GE.
That only took a few years...
That said, I do expect more uses for Promethium being introduced before other such things as, y'know, bugfixes that have been open for close to a year now.