CRYPTO20 is an autonomous crypto-only index fund that tracks the top 20 cryptocurrencies in the same way the S&P500 tracks the top 500 US company stocks. C20 is the fund’s token, and represents an investor’s share in the fund. Token-holders are able to liquidate the C20 token for their share of the underlying assets via the smart contract.
The SALT platform is meant to facilitate getting a loan, where the company holds your cryptocoins as collateral while you don't pay back the loan.