I think the main reason is that the visualizations are driven by audio analysis, which is often inferior to actual videos edited by hand. This isn't designed to compete with videos made by people, only to provide a good-enough substitute.
I could implement a video editor to let people have more control over the visualizations, but people can already use existing video editors to do that instead if they really wanted to. So I decided that it wasn't worth the effort.
I think the main reason is that the visualizations are driven by audio analysis, which is often inferior to actual videos edited by hand. This isn't designed to compete with videos made by people, only to provide a good-enough substitute.
I could implement a video editor to let people have more control over the visualizations, but people can already use existing video editors to do that instead if they really wanted to. So I decided that it wasn't worth the effort.