With only a spot market, short sellers need to borrow assets from holders and then sell them. This requires paying interest and requires holders to be willing to lend assets to the short sellers.However, since we have Perp now, long positions sometimes also need to pay a funding fee to short positions. While short sellers are selling an asset they don\'t own and may not have in the future.While Perp makes mathematical sense, I think there must be some issues here.