Correct me if I'm wrong.
Ethernet technology is being primarily used in LANs. And we use PPP in serial links. To carry IP datagram, we can use either layer 2 technology, such as Ethernet, or we need some layer 2 protocol supporting IP like PPP, if there is no layer 2 technology being used. PPP is a data link layer protocol for two devices connected directly without any device between them according to Wikipedia.
1) Can I use PPP to connect to my router from PC? If no, then why?
2) Why I need PPPoE? Where it is used (in which situations)?
3) So PPP was created only for the situation if there is no layer 2 technology? So we could use PPP.
It will be wonderful if you give me detailed answers and additional informations if I misunderstand something.