Charge backs have always been a worry for streamers, especially when receiving large donation amounts. With this feature streamers can toggle a signature donate system for a certain amount. This way a streamer can say, hey if you want to donate x amount or over you need to provide your signature. With this feature in place streamers will have more protection against charge backs as they will have sufficient evidence of a real payment. This is a large thing Paypal suggests for keeping the "seller" safe. With this intact, even if it's not perfect, streamers might be able to defend themselves from refunding.