Re: What is your view about p2p smart contract on ethereum?
it is a structure where downline pay upline
Can you specify which smart contract you're specifically talking about? But based on your description alone, it sounds like a typical ponzi scheme. A big no-no if anything.
I don't know if it will be a smart contract for any project, but I believe the description above is exactly that of Ponzi 
No one model is more appropriate to the description of OP And of course, my point is to reject the Ponzi model, it should not appear in the smart contract. HIYP should not exist to cheat people 
Please stop any of your ideas about this model!