It will do precious little to improve security. Technically, it is not a breach of anybody's privacy because there is no privacy in public spaces. But it's yet another example of the kind of surveillance state China is. Mass surveillance is not the sole province of dictatorships like China. Democratic states in the West also engage in mass surveillance. There are security cameras everywhere in Western cities. Also, despite the fact that mass surveillance of the domestic population is restricted by law, the Five Eyes agreement, parties to which the USA, Canada, Australia, New Zealand and the UK are, allows the governments to circumvent the laws by spying on each other's citizens.