He is not completely wrong, but we could say the same about gold for example.
His vision about investment is like "whatever generate cash flows", and bitcoin obviously does not have any cash flow, but it do have a worth based on asks and bids. So it is gold and silver.
yeah exactly that is a succinct way to put it. Investments according to him generate a cash flow for the owner. Which is why he only believes in buying something to hold for a very long term, because he doesn't believe in speculating. So he cares about dividends and not about the future price of thing, which means he doesn't care how many billions of dollars he is worth, he cares about how much cash it generates in regular dividends to him.
Though this means that proof of stake coins are investments. Because if you stake all your coins it generates income for you.