You can, but it's a slow process. Most of the value I've gained on the account is from winning reward cards and buying in the market when I've earnt enough DEC. The card prices have certainly shot up and it's that rise in value that has given the rise in value to the account.
I'd say that breaking bronze league and moving into silver will be the position for better growth. I'm getting close to that now. If I played more I may have gotten to this point much sooner.