Readily rewarded with premium currency. All features unlocked for free, no need to waste time gambling.
Paying for the pro permit (insane value), unlocks massive quality of life upgrades that let you continue to enjoy the game more.
You never feel as if you're forced to buy the pro permit to enjoy the game. Only if you really enjoy it, at which point, you'll be so far into the game that you'll think "eh, why not? I've been here a while".
Great theme, nice art, thought-out mechanics, and almost no bugs. Through and through, a very well made game and app.