It's different from your hourglass in that the computer is controllable. Each sampled random circuit requires choosing all of the operations that the computer will perform. You have no control over what operation the hourglass does.

It won't be factoring large numbers yet because that computation requires the ability to perform millions of operations on thousands of qubits without any errors. You need very good error correction to do that, but luckily that's the other thing they demonstrated. Only when they do error correction, they are basically combining their system down into one effective qubit. They'll need to scale by several orders of magnitude to have hundreds of error corrected qubits to do factoring.