well, the intended logic behind is: as the pipes are underwater you need a way to "move" the liquids up and down (over-water and under-water), or at least a visual element that gives that sensation, so it doesn't look weird.
that's why before this update, you'll need to use the undergroud-normal pipes to connect to the underground-underwater pipes, giving that sensation of transportation.
now, however, if you literally try to just built pipes on the coast, you practically can build normally, just start placing the underwater ones when you reach the water. at the end, the visual effect it gives is odd, but it works (which is what most people actually want)