It depends what card you get.
I get the Lord Arianthis, where cheapest price is in the moment 1.3$ and the black dragon with cheapest price 4.24$ in the moment. But if you card like Vampir, Sea Genie, Rusty Android or Highland Archer they are nearly worthless. So if you have luck you can good cards, but if you see it as work to earn money I think it's not worth, because chances to get some of the legandary cards are not so high and mostly you get common and sometimes rare cards.
So if you see it really in financial way I would say clear no.