In some routers like Ubiquiti's UniFi Security Gateway, when you want to connect to internet via PPPoE, all you have to do is go to the web GUI or controller, go to WAN settings, hit the dropdown button, select PPPoE from the choices (Static, DHCP, PPPoE), input username and password, then save. It's all that easy.
But when it comes to Cisco router things get so complicated. Just like this one:
Why can't we just go to the interface, configure it as PPPoE client mode, then input username and password?