Why only now
A drone needs light batteries, small and precise gyroscopes and accelerometers, GPS and a powerful computer for stabilisation. All of these became cheap thanks to mobile phones. A quadcopter with four propellers is mechanically simple; the hard part is the software.
Rules
Common EU rules have applied since 2021. Drones over 250 grams or with a camera require the operator to register, and the pilot must pass a basic online test. You may not fly over people, near airports or in restricted zones.
FPV
With FPV (first person view), the pilot wears goggles and sees directly through the drone's camera. These fast drones are used for racing and action footage. Drone racing has even made it into games, for example the Wasteland Circuit event in Rainbow Six Siege.