Simple fact: Bakkt will custodian all bitcoins purchased at the end of each day (futures expiration).
The issue was never about whether the net difference between long and shorts (bitcoins purchased) is physically deliverable. That doesn't speak to whether all contracts are fully backed by BTC at all.
It's funny to me how we went from opposing trust, to trusting institutions to "back" contracts with BTC, and now we're even trusting every word a banker says. This is the evolution of Bitcoin users.
You are making a second point, but he said "btc are not held in trust." That is not true. They are held.
You left out the second part of the sentence, which clarified that futures exchanges don't need to issue contracts on a 1:1 basis to the underlying inventory. Nobody said an inventory doesn't exist, nor that Bakkt's contracts wouldn't be fully backed by equivalent value. I'm just not confident that in a "bank run" scenario that all contracts would be physically deliverable in BTC. I don't really care either. But it's an additional reason why I wouldn't store BTC with Bakkt, beyond those that apply to conventional exchanges like Coinbase.