The bacteria in a bottle products all make the same claim. Instantly cycle, ready to add fish immediately. And that is... largely true.
However, who in their right mind dumps a bunch of bacteria in, then stick a dozen huge fish into a tank right away? Even with the bottled cultures, you should always stock slowly.
Don't get me wrong, I love the tanks they build. Some are ingenious, all are creative. I love that they are generating new interest in the hobby. But they are creating very unrealistic expectations and endangering the animals.
My two cents.