Why is Keyboard Maestro’s conflict palette rarely mentioned as a leader-key alternative to LeaderKey.app or Karabiner Elements—are there performance or feature trade-offs?

It has certainly been discussed in this forum, for example at various points in the topic Leader key implementation in KM. Beyond that, well, people are in general not always aware of what KM can do, and when they do have some awareness, a ready-made, polished solution in one little utility may still have more appeal than making and tweaking macros.