Commercially they are used by realtors for example. They are used for weddings, in sports, nature conservation, and much more.
Certainly the police and other security groups have found them very useful and they have certainly saved lives.
Drones are dangerous
However, drones are potentially dangerous. They could cause serious injury or damage should they crash. Typically such a crash is unexpected, so a car driver might swerve instinctively and cause a secondary accident.
With this in mind, you need to be sure that your insurance will cover you, both for the loss of your drone and 3rd party claims.
There have been several near misses reported by airline pilots coming in to land. So you should never use a drone in the vicinity of an airfield.
How to use a drone safely
In Canada the use of drones is regulated by Transport Canada. Fortunately they allow you to use small drones without special permission.
For drones over 25kg you need a Special Flight Operations Certificate.
Go for it
You can buy a small drone for a few hundred dollars. So why not treat yourself and get to know this exciting new field of videography? There is a learning curve (see this CNN article). At this point the field is wide open.