Actually they are pretty good, sturdy and delay the burglar and make them make noise. Chinese people are nosey and will keep an eye out for dodgy prowlers.
We have them, we saw a guy eyeing up our locked gate. 2 days later, 10 cars nearby were smashed into, big hoo hah, police, all sorts.
through the night someone tried our front door one time.
our neighbour above complained (tossers) that we put up cages without 'asking' them first. weeks later they wake up to burglars actually in their place. next day they decide to get the cages!
we are on ground floor tho, if i was up high, i wouldnt have them.
we actually live in a decent place too, so I'm surprised at the amount of thieving. nearby they had the 'wire through the unswrewed eye hole' situation, luckily our door is solid with no eye hole.