It's quite simple. They can't rely on repeat business because they screw over anyone who gets hooked into doing business with them. So they must branch out, looping in legitimate businesses to give them a whiff of legitimacy. Pet products are likely just another market segment in which they can deploy their misleadingly vague sales pitch and fine print to separate a new group of fools from their money.

Note that for the businesses, restaurant.com offers a legitimate function, enabling them to outsource the shady new business generation.

There is a sucker born every minute. If you are willingly led astray, and tend to fall for sales pitches or enticements that seem to promise that you can lose 40 pounds for $100, or that you'll get a guaranteed tax refund sight unseen, then these "gift cards" will be right up your alley.