They can take the other side of your other themselves, lose money sometimes, but make it up in the premium they charged you in the first place (or in the old days, from your other trading fees or your monthly subscription payment).

Cloud providers would be taking way less risk interacting with their own services than a broker does interacting with the market. Perhaps they would be more at risk from bad actors, but it shouldn't be significant: they could reserve this behaviour for people who have already spent, say, $100 with them so you can't abuse it at scale.