Unreal will definitely get better results out of the box, but it's also possible to do photorealism with significantly less overhead (particularly UE shader compilation overhead) - useful for single purpose platforms. If you don't need to support lots of specific editor or game features, it may be a valuable investment.

UE is definitely used to obtain simulation data in other domains (this is coming from first hand experience in big tech), but usually through scripting UE handmade levels in python which also needed convoluted server systems at the time (hopefully this has gotten better now).