Yeah but to my understanding, slot games are not their own games, they just host them. Plinko, Dice, Coin Flip, and the one with the rocket raccoon (I forget the name), are their games. In a sense, because there are variations of these games on similar websites. You can play those with the faucet money.
Naturally slots are made by them, it takes time and money to develope such a huge amount of slots, (and usually designers have to pay royalties for copyrights too), And you can even filter them by the developer. But does that really matter if we can use them to mine BFG tokens anyway?
Well, I haven't even tried the slots so don't ask me

I am satisfied with their simple, non-slot games either way, and I don't need to spend a bigger amount playing the slot games. And I like the fact that they currently have a faucet that you can claim regardless of whether you're low on balance or not.