Shopping carts for carriers

I know it's unsafe to click your car seat in on a regular buggy, but the Walmart by my house now has shopping carts specifically designed to hold car seat carriers. They have a bucket looking thing where the child seat would be and then a seat belt that goes across them and it seemed very secure. Plus it was awesome because there was so much space in the buggy for my groceries, although it was a little hard to see around to steer the cart, but I'm a shorty lol. Does anyone know if this is actually safe? Heard any reports about them?