It's not required by the EU. If not all the sites that have content not appropriate for children, such as porn sites, or Reddit, would need to implement this. A

It's not required by the EU. If not all the sites that have content not appropriate for children, such as porn sites, or Reddit, would need to implement this. And of course you wouldn't give your ID or credit card to a porn site. Google is the only company that started to implement this. To me it's not required by law but they decided to do so to get more user data. Also because having a credit card doesn't confirm nothing about your age. I use a credit card to buy things online since I'm 13, you can have a credit card even if you are not 18, simply your parents need to sign for it, but then it can have your name on it.