What would be worse for the USA: if China took control of the South China Sea or if China took control of Chase Manhattan Bank?

the South China Sea. The US will lose the geopolitical power in Asia absolutely. And that will affect the US more than a bank in the US itself.

The South China sea can not be replaced if lost. Bankers let China have them easy to replace no loss to the Country once gone.

The Japanese found out in the 1980s that owning things (including institutions) in the USA did them little good except as investments.

Nothing

Depends on whet they do with these things.