Well, they still cost 100k a pop
We do no-loss, so we have insane amounts of gold, but if you play normally and have to replace units regularly after each battle, the cash required might become a problem. Even within the no-loss game, I felt that the devs intentionally made the player pay insane amounts of cash for simple stuff (as I saw my purse going empty as well on a few occasions), just to limit them from becoming overpowered very quickly. Too many quests require you to drop 50k here, 100k there, or a 500k to bribe the school director in Inselburg into selling you 5 real princesses.