Re: "Think about the children" - Yes but not this way
I've long assumed that the idea is to have a file of dirt on all individuals in case they turn out to be "key" to something the government (or its associates) don't like. Then if, for example, you attend a protest and are spotted by the Forward Intelligence Teams, they'll have something to add to your "biography" as well as your presence at the protest. Per terabyte of storage, that's about 15k per person in the UK.