Its not the individual uniforms its the vehicles here. Military vehicles are camouflaged much like individual troops but changing a uniform is alot easier then repainting a tank or IFV. The capacity the PLAMC seems aiming for is true Amphibious Blitzkrieg. Rather then landing and establishing a beachhead then expansion to objectives. They intend to land mechanized light armor and assault to objectives with secondary forces following in the wake. The ZBD series is light weight in protection and small in troop capacity but fast in the water and well armed with light tank versions. They seem to offer half the capacity of the USMC's aborted EFV meaning I suspect a shorter amphibious range compared to EFV but longer then AAV7A1, M113, ACV1.2 or BMP series vehicles. They are intended I believe to land and assault as quickly as possible smaller landscapes like islands vs the USMC model which is based more on landing and establishing for larger campaigns across larger landscapes.
The PLA marines belong to Navy; the PLA Army has its own Amphibious troops, which are used to cross water and then fight on land. You're right that the Chinese marines are not exactly the same as the USMC.