A permanently purchased item in the game becomes less valuable over time.
"You get 5 times the items later in the game for the same amount of money you spent at the beginning, but you need 20 times more the same item to get the same progression"
"Clothes obtained in limited events have stats that get increasingly higher as the game goes on"
"some of the older characters and mechanics you can get from the gacha are much worse than others, typically because they're older"
"Pretty much everything you purchase is a token of some kind, so you use them up. Sometimes these tokens are for limited time events and the tokens expire when the event ends."
"As you progress and level monsters, the amount of food required to get to the next level increases sharply, making it very expensive to continue."
"As you level up, the costs of playing the higher levels are higher, with no discernible increase in winnings."