As a way to fight inflation. Most of the Goal pools will have a burn fee, and the fee is different for each pool. Please make sure to check this info on the pool you are going to stake. The burn amount calculated based on the burn fee is directly sent to the burn address (This is one of our ways to fight inflation). Note: Burn fee cannot be returned in any case. Since it's transferred to the burn address and we have no control to get that back.