Well first, the US is not restricting oil through hormuz, even Iranian oil.

Second, the oil market would disagree that blockading a choke point is not effective. The threat of Iranian missiles has reduced the volume of oil on the market. It's a measurable reduction.

And no China does not have pin point accurate missiles. The missed hits on Diego base with Chinese missiles demonstrate that. The nice thing about Iran is they use Chinese tech, and Chinese contractors. It's a good trial run to asses Chinese offensive and defensive abilities. So far they have proven ineffective against western militaries.

Even Chinese deep bunker defense is proving ineffective. Iranian officials are now taking their chances sleeping in tents as the deep bunkers are death traps.