Ships of the line were designed to make long, ocean crossing ships. They went to Asia. They went around Africa. They went to America. They carried large crews, tons of cannons, and huge amounts of cargo. They can work in smaller waters, but being capable of doing the extremes was important. They were pretty blocky, too, though.

Asian ships were mostly traveling pretty short distances. Chinese ships were traveling the coast or the rivers within China. Famous Chinese naval battles like Red Cliffs and the Wokou raids, that's where they take place. Flat bottomed ships were liked for being able to travel in shallow water, and those kinds of ships existed in Europe too for the same reasons. I've heard that this is one of the reasons the Mongolian invasion of China was such a failure. They used Chinese river boats that already had trouble crossing the sea, and sailed right into a hurricane. Twice. Japanese ships rarely left the islands. There was enough internal conflict that that's where the focus was. They were used in naval invasions, but still in nearby places like Korea.

SEGUE

The Koreans, like the turtle ships you showed, had a really strong navy. Nothing in Europe was that armoured. Probably the highlight of their whole use was in the Japanese invasion of Korea, where they fought along the coast, using islands as cover. You couldn't really remove them from the context they were meant for, something discovered in that war itself.

In short, ships were purpose built. They excelled at their purpose, and European ships excelled at theirs.