The 4k imagery is exceptional, allowing for close up details and it allows for whole roof inspections to be done, where areas were previously too dangerous to traverse.
Included below are a few examples of the image quality achievable with modern high quality drones.
I have RPA operator accreditation for remote aircraft with the Civil Aviation Safety Authority and my drone is registered to be used for building inspections.
It's just another service that I provide, to assist in advising you when buying a property