I think it could just be simple "if we actually own it we have an absolute say on ANYTHING that goes on and our mineral extraction and military assets cannot be kicked out EVER" whereas there's this fear that China will give them a better deal and they'll down the road in 5 years, 10 years, 15 years when the US is weaker make a deal with them, push the US out and that'll be it. But if the US seizes it, buys, etc, digs in like a tick then in 10 years, 20 years when the US is weaker they still have absolute control of the minerals and their exploitation strategy. They still have absolute control of it for military uses in missile interception against Russia and China over the north pole.

So it's consolidation of assets, power, land, the great climate fortress while the US still has maximum power. The time to build a fortress and defenses is not when you're already under attack and flagging but when you're strongest and can make your boundaries as big as possible. Critically for the US strategy to control China it's part of ensuring they have control of key raw minerals on top of markets that they can be gatekeeper for and force China to play by their say-so or else they turn off the supplies and turn off China's manufacturing economy.