Doorbell cameras are advertised everywhere these days. They are convenient if you wish to be able to see who is at your door. Most of them record to the cloud if you pay a fee, so that you can review what happened if you do not receive the direct feed. “Ring” brand doorbells have a feature which sends out notices when other “Ring” owners post about bad things which have happened to them, like mail thefts or car break-ins. Unfortunately I see many people commenting that their “Ring” did not pick up the bad guys. They seem annoyed by this failing.
The simple fact is that doorbell cameras are meant to serve one function, to give you a visual of the people who have come to your door, and (if you are a subscriber to their cloud service) give you a record of who they are. To do this satisfactory, the doorbell must be positioned so that it is able to observe people approach the doorbell directly. Many houses have the doorbell off to the side so that its field of view is limited.
I personally have a “Ring” doorbell installed at my home. However I also have a full CCTV security system that I have just upgraded to 4K (8MP) cameras. This system gives me a full 360 degree coverage of my home, with one of the sharpest pictures on the market today. Because the cameras have a 131 degree field of view my neighbors benefit from coverage by some of my cameras.