Although loan over-collateralization provides a high degree of security for lenders, it also limits the scope of DeFi lending to people who already have sufficient collateral to self-finance their own loan. Teller is a DeFi protocol which aims to expand DeFi loans by offering under-collateralized loans to the vast majority of borrowers who can't "self-finance" their own loans, but this comes at the cost of privacy and necessitates traditional requirements such as credit checks. Is it worth it? In this video, I'll briefly describe how both DeFi and traditional loans work, illustrate the shortcomings that Teller hopes to overcome, and give my thoughts on the merits of the project.