I could justify the cards back in the days (eons ago) when I played Magic, because they were at least collectible and tended to appreciate in value.
It's for this reason alone that I haven't looked into this. I think the pull of Magic and the like was the tangible cards and their value. Digital cards are worth exactly what you pay for them, when you pay for them, and then nothing at all. It might be fun for awhile, but when you realize how much you spent on cards a few weeks later, it would lose its pizazz, at least for me.