Because it is not adequate to use cases today. Today, you can set up DNS per interface and designate, which DNS accessible via which interface can resolve whic

Because it is not adequate to use cases today. Today, you can set up DNS per interface and designate, which DNS accessible via which interface can resolve which zones. So your intranet.company.com can go through specific VPN connection and the rest via your default route, for example. You can't do that with simple /etc/resolv.conf.