The core business of a bank is to gather up funds from investors to lend to borrowers.
By charging borrowers a higher rate of interest than is paid to investors, the bank makes a margin which covers its costs and provides a healthy profit for its shareholders.
The concept of peer-to-peer lending is to provide a marketplace where investors and borrowers can get together directly.
That way, it is possible for investors to earn a higher rate of interest than a bank will offer and for borrowers to pay a lower rate of interest.
In theory it is a win-win for investors and borrowers.