If China uses some of its airborne and amphibious forces to take the Pescadores, they will have a base for the next stage of the operation; the landing on Taiwan itself. But it is likely that speed will be the most important element. The faster the Chinese establish themselves on Taiwan, the better their bargaining position with the United States, and the rest of the world. If China does not win a quick victory, the economic sanctions start kicking in. Billions of dollars of cancelled orders from the United States and Europe put millions of Chinese out of work, and make the invasion very unpopular. Should the invasion prove unsuccessful as well, a change in Chinese leadership is likely to quickly follow. One way or another, the Pescadores islands will play a major role in any assault on Taiwan.
I tend to think the northwest direction is the way China will go, in order to go for the jugular in Taipei as part of an all-out offensive. And I suspect the attack in the northwest will go on at the same time as an invasion of the Pescadores.
Seizure of the Pescadores would be used not to assault the southwest beaches but to raid them and threaten to invade in order to freeze Taiwanese army units away from Taipei where the decisive battle will be fought.
I agree that speed will be the key to a Chinese conquest.
Still, there is one option where the Chinese might leave the Taipei region alone. If the Chinese find they need to invade yet calculate that they cannot win before we intervene, it is possible that the Chinese would want just the objective of establishing themselves on Taiwan to effectively divide the island in a ceasefire; and then prepare for the next round at a future date.
It is even possible that the Chinese might decide that the Pescadores are the objective. Again, seizure of this stepping stone would be to prepare for the next step of invading Taiwan. As a bonus, knocking down the door like that to expose Taiwan to direct invasion could scare the Taiwanese enough to get them to pull a Ukraine and enter China's orbit.
One way or the other, whether in one bite or several, the Pescadores are important to Taiwan's independence.
