Green roofs have a huge list of benefits.

1. They keep the place better insulated, both warmer in the winter and cooler in the summer.
2. They help reduce local air temperature, particularly in cities, by reducing reflected sunlight / radiation.
3. You can farm animals on them(see https://oldcountrymarket.com/ )
4. You can have a rooftop garden and bee colonies. See the western half of Vancouver BCs Convention Center. Where they maintain a wildflower garden and beehives on the roof of the building and the chefs inside the building harvest honey from the beehives. ( https://www.greenroofs.com/2022/08/18/featured-project-vancouver-convention-centre-west-expansion-project/ )

Only fault of the realtor is they didnt get the place landscaped prior to the photo.