Out of the box, the Atlas switches won’t automatically switch their thrown position like the Fastrack switches do. However, the points are sprung so if a train goes through a switch that is thrown the wrong way, each set of wheels on the train will move the points so the train does not derail. As each wheel set passes the points spring back to the initially thrown position. I have occasionally run a train through a switch that was thrown in the wrong direction and never had a derailment, but I don’t know how reliable the spring return would be in constant usage.
I had read the same thing back when I converted my layout. I tried them relying only on the spring tension. I had derailments frequently to the point of frustration. I suspect that’s why Atlas made the non-derail boards to go with their machines. Admittedly, I did not tinker with the spring tension, so maybe there is a solution to be had there. DZ-1000s solved the problem with active movement of the points and were only about 20 bucks.