I love his demos (just linked Trip to Mars in the oldschool group on Facebook an hour ago as it happens
). But that doesn't mean his (or others') demos deliver the performance expected from exploring the Blitter fillrate. Here, he uses the Blitter because he basically has to (because of adding low-poly objects on top of Richter's backgrounds; re-using the palette). A CPU routine would be something like 3-4x slower than the Blitter on top of a picture that you have to restore.
This is why I wrote about reduced slick scenes in my previous post, in demos the tendency was to not solve the problem of fast complex Blitter 3D but to put together an enjoyable presentation instead. Vector Preview by Tai-Pan was a better attempt at a Blitter 3D engine, but it doesn't have scenes comparable to contemporary 3D games.