Why not both like Merchant Marines.

Dual use sealift is just common sense. Too many years of stupid western analysis that PRC would waste $$$ to build dedicated TW amphib fleet, and point the absence of one as PRC not ready to invade TW. Reality is every $$$ PLAN spends on sealift is one not spent on weapons shooting back at US+co.

PRC RO/ROs (and a lot of other commercial shipping) are indeed build to military standards for TW scenario. Used for shipping cars like they're suppose to during peacetime to let that capex work, and armor vehicles during war.

Comparable RO/ROs have been actively involved in invasion TW training/exercises. PRC RO/RO numbers a couple years ago was enough to land 7 full PLA group armies (300k + equipment) on TW in about 10 days, or every US Army Brigade Combat team in 5 days. They'll probably have enough RO/RO sealift to cut that down to 2-3 days in a few more years.

China still has an amphib fleet, and there are reasons to use amphibs for at least the initial forced entry operation, but once you have a beachhead the dual use ROROs are a good way to sustain and reinforce the landing force without needing to capture or build a port facility.

And it’s not like the amphibs are only useful for Taiwan; there are plenty of disputed islands in the South China Sea worth fighting over.