Unfortunately I’m not a member of Poliigon and I can’t say 100% how the textures are presented there. But they’re likely just high resolution photos taken specifically to be textures. At best, they’ve been modified to be tileable.
Either way, they can certainly be used with a model’s UV’s. The same way we projection-painted (stenciled) the pancake texture in this course, you can also do with poliigon or other photo texture source.
