He's right about the shorting: to short it using futures is, in a way, to side yourself with potential ruin. Only through put options can you safely do this.
The risk is that if the price of BTC is above 10k, then I'm out the money the put option cost me.
Option:. Purchase the right to sell the asset at a certain price & time. If the price is higher, then politely decline the option. The value of the option is zero, but you've already paid that upfront.
Future:. Purchase a promise to sell an asset at a certain price & time. If the price is higher, you are still committed to make the sale. Safe if you hold the underlying asset in escrow until the strike date.
With buying puts or similar construction that involves optionality, if you can buy them at a nice price, you're not as dependent on the intermediate path taken by the price.