You never, ever, ever have to play "moronic AI" if you don't want to. The only time when you would is when you have 29 or less electrum or go to PvP1 and then lose. So why should zanz imbalance the game by removing the entrance fee for every single AI level just because some people aren't smart enough to keep an AI3 grinder (that you can build 10min into starting the game) to fall back on when they get under 29 electrum?
Seriously, if anything, the gold cost of matches should be increased. Right now, if you have at least a 50% win-rate against any level, you're more than likely to make a profit. The lowest amount of electrum you can win is 100% the cost. So if you start with 10 electrum, play AI3, and win with 1HP, you're going to end up with 20 electrum without spinning. If you EM AI3, you'll end up with 30, and if you get all three spins, you'll get +15 for bonus electrum from spinning and 60 electrum worth of cards. And if you're facing FGs, then it costs 60 electrum to play 2 matches, but if you win them both, you have a chance of winning a 1200+ electrum card.
Because of how low gold costs are when compared to rewards, we play the fastest decks possible and focus on speed rather than win-rate. This is the reason why we notice games not as strategic duels full of turning points and lip-biting but as one of the many in a batch until you get enough for that one upgrade. The reason why the grinding is so boring is because the gold cost is already so low. Decreasing the gold cost would only make this worse.