After playing the game myself, I think this is going to end up burning a LOT of Dec over time. Ticket costs ramp up quickly already and nobody has even got to league 3 yet. Once you start adding in additional sinks like the Soul Boxes and probably some kinda fatigue removal option I think it should really get going.

Edit to add: Personally I'd really like to see some kind of unlimited play mode. No rewards or souls earned toward league advancement but no fatigue costs either. Some way to practice and learn spells, towers, maps, etc. Maybe like unlimited waves on our current map or something. I think this game has real potential to attract non SPL players. It is a fun game with out the crypto aspect even and I could really see this be more general masses popular.