Well it's not a bad idea certainly as you keep your money... and I guess it's the only altrnative to grinding levels first before taking them on (and it helps if you want to know more about the E4's strategies).
But I don't see much discussion out of this tbh, as there's not much else to say...I'll be closing it then because of that - also seems more like a question anyway in which case it would fit more in the Help thread.