Will there be no way for people to buy in and own shares of the DAC's profits?
No, it's not pointless. Notice David uses the term rolling peg. Meaning it's not fixed at a specific value versus US$ forever. Think of it as a stabilizer. It will take some of the volatility out, but price will still be able to go up and down.
Actually it's a little like a modern peg in fiat. The hard peg like Swiss franc that broke in 2015 has a long tradition of failing because at some point circumstances have changed so much that the cost of maintaining the peg gets to high. The modern peg (often not announced as a peg) has a target corridor that allows some deviation from target price. Also that target is adjusted when necessary.
We expect the effect of the peg to be a price that moves more like bluechip stock or fiat as opposed to penny stock and crypto.
What is DAC?