Neither Taiwan nor the United States can dominate the Taiwan Strait to deny China the ability to use the strait as a path to invade Taiwan. So this is a good measure to fight in the strait to inflict casualties and deny China free use of the strait:
The [Taiwanese] Navy has submitted a request for NT$31.6 billion (US$1.02 billion) to build 50-ton fast attack missile boats, as part of the national annual defense budget which was submitted for legislative review on Friday.
According to a high-ranking defense official who asked not to be identified, the missile boats are part of an effort to strengthen Taiwan's asymmetric warfare capabilities in the face of a growing military imbalance in the Taiwan Strait.
Assisted by minefields, land-based anti-ship weapons, helicopters, and aircraft, Taiwan can use those boats--armed with two anti-ship missiles each--to at least increase the price China pays to land troops on Taiwan. Which may deter China or which might at least slow the Chinese down and reduce the size of the Chinese army that lands, making it easier for Taiwan's army to counter-attack and drive the invaders into the sea.
But even though this type of vessel is important, Taiwan still has a need for larger ships that attempt to control the seas east of Taiwan so their lines of supply are held open for resupply and possible reinforcement.
And don't forget submarines that can both fight in the strait and blockade Chinese ports.
