Last I looked, jumping around like crazy was hard for compilers to follow and would cut short some optimization. Not an issue when Knuth was originally writing, much more of one today. It's possible that this has changed, though - it's been a while since I played with this in depth. There remains Dijkstra's issue that it can be hard for humans to follow in any event, which Knuth didn't really directly dispute - his position was that there remained some narrow use cases where the speed improvement was worth it, which is different than "jump around like crazy".