The majority of training footage of the PLAN conducting amphibious landings show a blue ocean behind the landing marines. In low light situations, yes, the colour of the ocean can change but low light situations are hardly the time camouflage is most useful.The Blue pattern I call Littoral pattern is supposed to be optimized for the South China sea area of operations. In reality it is a purely vanity pattern meant to show the Elite status vs PLA regulars. Lots try to defend it saying its for the ocean but the ocean changes colors based on the lighting. In the late afternoon of the tropical zone sure pristine Blue but just as often emerald green, or Grey to black at night or brown when silted up by a amphibious landing.
Is the Taiwan coastline littered with riverine and swamps? Or is it more packed with beaches? The PLA equips for the most likely scenarios, not possible-but-unlikely scenarios. Like I said, if ever they needed to ditch the ocean camo, they'll do it like my pictures show.As your Marines are assaulting they are aiming inland and not just going to play on the beach. If they need camouflage they are likely also to want cover. On a beach the best option for that is the ground, the sand. The ocean is not really going to be the best match again varies based on time of day and conditions. Add in that said beaches are often urbanized or rocky which means frankly better to just wear deserts.
But there is another factor here not all landings are into beaches from the sea some are into rivers and swamplands for those woodland. A even better option would be transitional pattern like Multicam as there is likely sporadic areas of greenery.
PLAN marines are not US marines. The US sees fit to have her marines fight inland battles and even has them do occupation duties. China does not view her marines that way. China's marines are to do your so-called '5%' and then pack up and go home. The Type 072s and 071s will bring army reinforcements who will continue the fight inland.As to Marines fighting in land. That is there function. The amphibious transport and transition, the establishment of a beachhead is impressive but its just getting to the fight, it represents maybe 5% of the actual operations. The PLA knows that, that's why there landing vehicles are armored and Armed like they are. Not for the beach for the battle.
And what use is a rotten chocolate milk camo when you end up landing on a Taiwanese beach with the vibrant blue ocean behind your back?What is the use of a pattern meant for the ocean if your landing up a river with water the color of rotten chocolate milk?