It is just luck whether they last a long time. Worst problem is rust attacking the steel mounting bracket.
I agree a single 10 watt would not light up a large area but combining in a group gives a large cover. I have 10 fitted at the moment switching by 3 separate PIR detectors.The further you get into the garden area or garage, the more lights will come on in groups of 3 plus one on its own. There are also 5 strips of 300 LEDS each that use 25 watts per strip powered by batteries charged by solar panels. That is 1500 little LED dots all at once using 125 watts switched by a microwave motion detector inside the garage near the window.
Electricians love to play in their own house.