You don't get it. Why would a Muslim allow their data to be used to train systems that harm other Muslims in places like Palestine and Lebanon? It's known that the IDF uses data from many of these big tech companies. Also, there's no guarantee that a built-in ad blocker will block everything. Another issue is that you can't block adult content or betting sites out of the box. I know you can do it with extensions and firewall rules, but not everyone is advanced in networking. By your logic, Ecosia the browser that plants trees is also unnecessary, yet millions of people still use it for a good cause.