When a loan with the BuyBack guarantee defaults (has a delay of 30 days), it is bought back by TWINO, returning all funds invested in the loan plus interest for the 30 days of delay. Thus, you have to look for new investments in order to make your money work.
The difference with the Payment Guarantee is that the loan is not bought back after the 30th day of delay. The loan status changes to “Defaulted”, and you are no longer able to resell the shares, however you keep receiving monthly repayments of principal and interest in accordance with the original loan schedule until the loan is fully repaid.
For an investor payment guarantee allows for slightly more stable cash flow. Essentially when you used to invest into a loan, and it got delayed then the payment was made late when the BBG triggered. With the payment guarantee the idea is that the interest payments would always be made on time due to Twino taking a role in ensuring the payback. I’m honestly not sure how much of a difference it would be for most investors – the delay for BBG loans isn’t really that long most of the time.
Buy back guarantee kicks in 30 days after the loan has been delayed with principal + interest paid to investor. Payment guarantee will still make payments on schedule, even if borrower doesn't make payment.