Not necessarily. Right now the industry is largely unregulated, but that's more a question of enforcement than any sort of real legal protection.

In the US you can't build a slot machine that accepts money and dispenses tokens that have value. That's often how things operate in Japan, but the same model is generally illegal in the US.

It's questionable if spending real money on virtual currency to buy "loot boxes" that randomly give things of value is legal. And if that's legal, it's not obvious if changing the rate of rewards is legal.