You can't get epic cards from anywhere else [content removed by FirstLady], but 2 devo'd legendary heroes with lvl 10 skills...
It all depends if you have enough spared resources and are willing to use for it.
Personally it is not worth for me.
Just as Cichociemiak stated if you have the resources and are willing to do it then its worth it. I personally have the resources to do to but I am too lazy to get 10 heros devod just for the smallest chance at getting a spare dyna I have no use for.