Where at all does the game kinda imply you should be CCing at 30? Also, as pointed by many with any game experience, it's not at all unintuitive. As for the second part, using silvers in combination is perfectly fine to get CR/SU, you just don't have the loads of silvers to spare early on if you also want to be CCing more valuable units, which is the best long term play. If you're suggesting that the game should be actively telling you the best way to play (especially so in a F2P game) ... then you have much to learn.