Q1: Risk itself is a huge cost. Although risks include profits and losses. You have to remember that not only losses are a cost, but potential losses are also a cost. The company eliminates the risk through hedging, which means this cost is saved.
Q2: Generally speaking, the so-called buyer and seller depends on whether the investor's position is mainly buying or selling. If it is mainly a buy order, it is a long position, that is, a buyer. If it is mainly a sell order, it is a short position, that is. seller. For any specific transaction, there must be one party as the buyer and one party as the seller. In our lives, we appear as buyers when we consume products, and we appear as sellers when we provide services and earn wages. So it is not surprising that there are two roles in one person.
Q3: There is no tax on profits from futures trading, unless it involves physical issues of delivery, which will involve VAT.
Q4: As a hedging party, because there are warehouse receipts as collateral, the funding requirements are not as strict as those of ordinary speculators. As for what you mean by value preservation and holding costs, I don't quite understand.
Q5: Delivery will definitely be troublesome. But there may be price differences and room for arbitrage. As long as it does not converge with the spot price, there will be room for arbitrage and someone will seek delivery.