It matters for the same reason I think banning encryption in the UK is a problem, even though I don't live there.
It matters for the same reason I think the millions of people riding around on motor scooters here without any protective equipment/clothing, often against traffic in the parking/emergency lane is a problem.
The more data people give to an organisation like Google, the more power it gets.
The more power it gets, the more data it gets.
The more data it gets, ....