the major downside is that you have to sqirrel grind pennies to even cough up the amout for that stone.. that's several ingame years, because you still have to buy all the other stuff for large sums in order to progress, and whatever you do will give you pennies, so you have to cheat or you grind your balls off.
it sucks if you have to cheat a new game in order to not lose interest because of the giant imbalance between two game components.
would he cut a 0 (one digit) off every price, the game would be much more enjoyable without cheats.
the 'harvest ETA' always says 3 days, but it ain't. even with the garden blessed it takes a week or more no matter what you grow. so that source of income (15 per day minus days off) is as grindy as the night patrols (because you spend 30!! patrols for the first promo: 1 -> 5 gold, and 70!! for the next one: 5 -> 15 gold).
then you want some event to happen and have to spend 50 for something, at least, so that's 2 days income for one event, 3+ days income for a one cheap item, weeks of looping just for gold if you buy rings or cake.
it's imbalanced to the worst.
maybe the goal was to generate a longer play time, but i sersly doubt anyone is still interested after what 10-15 real life hours with only so little gain.