Trust: You need some collateral to give the other party the loan and to make sure that the person who gets the loan has a mechanism to repay that loan. This needs to see some personal data and thus reduced interest from cryptocurrencies.
price volatility: Cryptocurrencies are highly volatile and therefore must be converted using dollars, which may mean the need for a conversion of the local currency and thus revealing identity in most cases.
We can't agree more here, trust and price volatility are important aspects for any use-case involving crypto-currencies.
To counter trust factor, there is a KYC/AML module integrated into our P2P lending platform to ensure authenticity of users and making sure all loans repayments are paid on time.
To overcome price volatility, we have LVR (Loan to Value Ratio) Calculator deployed in our platform which liquidates the collateral at certain set of LVR point. To bring in fiat currency into the system that is something linked with client's business decision as it involves a lot of legal formalities to implement fiat currency.
More can be showcased over a demo if that interests you: https://www.antiersolutions.com/p2p-lending-software-development/