They can buy stuff with it that can make everyone's life worse.

It adds risk to the money itself, that if the money becomes too valuable, it consolidates inordinate power into a single individual's hands.

It's purchasing power though. Optionality not projectable power. He can only sell 4% of the bitcoin supply once.

You think money only buys physical things? You fundamentally misunderstand what money is. Money is a promise. You can get someone to do anything for money. If you have enough money, you can get anyone to do anything, if not directly, you can pay someone to use force to get you to do it. Money is power. Concentrated money is absolute power.

Settle down cowboy, it's just optionality. You have to exercise that optionality to realise any power. You have to spend your money. Money can't buy everything. Money can also buy anything.

The power is not in his hands at all. MSTR and it's Bitcoin are a regulated entity owned by the shareholders. Even if 4% of the supply was owned by an individual, how is that a risk? The worst that can happen is that it was sold all at once and the price dipped briefly. Big whoop.

You presume money is constrained by the state. When you have enough money, power functions in the opposite direction.

I prefer the outcome that it will all be sold at once due to a market correction rather than the alternative, which is a single corporation controlling a significant portion of the money supply. Note, this is a fundamentally different problem than ETFs custodying large sums of bitcoin.