Originally Posted by
Yelsha
The problem is that Banish incomes grow exponentially because boss HP grow exponentially, compounded with the fact that players damage can grow exponentially too. Yet the only, "cost" of any upgrade that grows exponentially is runes, which grow at a factor or 2 while banish hp grow at a factor of 5. Other costs, such as blacksmith, talent, and cards (in terms of the amount of credits spent to gain a certain amount of spirits) exhibit linear, or at most quadratic growth.