I thought about it, and I see no reason why water temples could not be made of marble. I made the animation on marble where the gold leaf fades and reappears, much more subtle than what was there before. Additionally, black and white are colors that tend to match anything so you should not need to edit your old Prismarine builds too much with this pack anyway.

Faithful Blue Version was made, so you can experience Minecraft's color palette as was originally intended and have an easier time making builds that are pretty to others on multiplayer servers.