I believe you're supposed to be able to toggle between the old graphics like you can with the Halo remasters.

It's weird that Lara and presumably the other human characters are the only ones getting PS2/PS3 quality models and then everything else is going to get this weird treatment. Tomb Raider is an interesting case for this kind of remastering anyway since the gameplay is heavily grid-based and the blocky level design is tied to it, so the levels now have high res textures and modern lighting but everything is still cubes