>I thought "synthetic data" it's something that rarely shows in training image recognition

On the contrary, it is used to train models but it cannot adequately capture the long tail of weird events in the real world. Hence, it cannot be relied upon, as alluded to by the parent commenter. With reference to using data collected from a simulated environment vs real world ─ this subject was discussed at some length by Elon Musk and Andrej Karpathy, at the Tesla Autonomy Day event a few weeks ago.