Ray tracing is super old, was being done (well, okay, in theory) in the 1960s. Trying to do ray tracing is how ray casting came about. Which is what Wolfenstein 3D does, it literally sends out a ray to scan every column. That's why its dimensions except depth aren't variable.
A PS2 VU doing ray tracing shouldn't be surprising considering what they had to be tapped to do to actually make games of the era. Look at how non-complex all of those scenes are especially in terms of colors and framerate, they're using its overkill drawing power to do something nobody would do in the real world. Some of those PS2 original demos did similar stuff in terms of not drawing polygons regular but instead drawing complex objects on the VUs. That's where the nonsense speculation that you could draw an entire world out of voxels or entire lakes out of particles on the PS2 came from.
The one VU (I think it's VU0 that everyone used?) is so much overkill versus the rest of the system that there are PS2 games that do absurd things like not cull backs or draw non-visible polygons because the fill rate just blows through it. The games that ended up doing fake bumpmapping were all doing things like absurd numbers of extra draws. There are PS2 games that do full screen effects (heat haze, lighting, motion blur) then erase it from all but a certain part of the screen that nobody would ever do as full screen first on any other hardware because it can redraw so fast. This was driving the PCSX2 people crazy for a while IIRC because you can't really get a modern graphic card to want to just do it without responding ARE YOU NUTS NO ONE SHOULD EVER DRAW THIS WAY BUT OKAY until their code got more advanced.
Amusingly, the vector units weren't really popularized ever, it was all the EMOTION ENGINE and GRAPHICS SYNTHESIZER, but almost every developer quickly figured out you couldn't make a modern game on the thing without using the vector units. Or at least you wouldn't really want to. This later created Xbox port problems, and stories about how it was slower than the PS2, because the Xbox almost perfectly has its main bottleneck in bandwidth in the same place the PS2 is overkill. (Think CPU to RAM to CPU basically.) The faster clock and more standardized nature of the "Pentium III" help make up for it, but there are ports where it's not done correctly and the framerate will tank trying to do things the Xbox should not even notice happening. MGS2 for example.
Funny enough, I've read that lots of this stuff was comparatively simple to move from PS2 to GameCube/Wii because it similarly has some overkill spots regarding the RAM that combine with the higher clocks. I speculate this is why the GameCube got so many PS2 ports where storage wasn't an issue even late into its life. Stuff like the Splinter Cell games come to mind, where Xbox was a completely different game. Double Agent even came out on both the GameCube and Wii.
