Just a sign that investors are just buying BTC and then put it in their wallet that they have total control of. They don't want in exchanges as they are not going to trade buy hold bitcoin for many years.

As to who is buying, it's obvious, retail investors, average joes, anyone that has capital and willing to risk in BTC because they know that it can be an hedge, store of value. And in the next coming months, we might see it hitting 6 digits.