I think the question is- does such a seizure (however justified) and resulting turmoil and consequences benefit China- whether it be in regards to its role in the emerging multipolar order, and its continued development under state-controlled markets/capitalism?

Personally, I don't think so. The present course is seeing China outcompete the west, diplomatically, economically, and increasingly technologically- it harnesses the productive, competitive advantages of capital, while maintaining the dictatorship of the proletariat, and its present approach has also shackled western capital to it (despite their attempts to contain and destroy China), and rather than alienating non-AES states and non-socialists across the global south, presents a development model and partner that they not only can work with, but can engage deeply with and admire.

The seizure of all Chinese billionaires' assets out of nowhere, would imperil all this. And for what? China already has capital controls and countless other regulations in place to manage its capitalist class. Unlike the west and most of the world, China also actually enforces these, with harsh- if necessary, even lethal- consequences for criminals regardless of wealth. The rules are already in place, capital is subordinated to proletarian rule, while still being open for business. Such disruptive actions in contrast could stand to imperil the unique balance that has over time, been perfected (not that it's perfect- but it is undeniably an achievement, perhaps unmatched in human history), and this is during a time of critical development in various fields- increasingly competing with the west technologically, working alongside many partners for the integration of Afro-Eurasia and the global south, expanding China's development and prosperity to every remote corner of the country, resisting encirclement and entanglement in the face of a increasingly deranged and declining west, and creating the foundations of soft cultural/economic/political power that can compete with the west, and building China's infrastructure and industries up to ever greater heights. Why risk all this, for some puritanical short-term (if even that- I doubt it) gain?

Once again I feel I have to state- the present system China has fashioned, has produced results unlike that which any other state has delivered, and this is without imperialist loot, plunder, and lebensraum no less. And the present system is not done yet- China has not yet reached its full potential, but also, its work is not done in uplifting all of China and playing its part in the uplifting of the world in turn. That's not to say that it is perfect and can be left stagnant- but such rash actions could threaten everything.

Its pretty consistent with Dengs/Xi's and Chinas political apparatus's understanding of how they are building socialism. The excess that neo-liberalism provides generates enough structures that can then in turn be used to advance socialism.

Its not the existance of them that matters, its how they are regulated and taxed.

If you just took billionares money (which they already do, through tax...) then there would be no incentive to build up productive forces, within the private sphere.