I agree that on the Ipad and other devices there is protection, but when my wife got it she didn’t even think about doing it (I did it on the other devices) before she let the kids have a go.
But the other issue is – why aim a game at under 10 year olds and have in-app purchases, especially where it promotes buying gems which cost between £1 and £70 – My kids don’t understand the value of money and she didn’t realise it was real money (although she does not after I told her this means no birthday or Xmas presents for her – which incidentally made her cry this morning)