Knife tool cuts through the whole geometry (whatever viewport you cut in) if you slice a single polygon from edge to edge, while Easy Split cuts on the frontmost polygon(s). With Knife tool you can do what you are saying, but with almost zero control. If you want to prove me wrong, do that by posting a video showing how YOU use either Knife tool or Bandsaw the same way Easy Split is shown in both videos Sensei posted. The only thing in LW that can be compared wiht Easy Split is Add Edges tool, which is not as fast as Easy Split.
As you may have noticed, Easy Split should be used in perspective view on the actual polygon(s) you are viewing. If you want to cut through whole objects, there are better tools, such as Knife or Bandsaw. If you, for some reason, thought that Easy Split was created to replace any of those tools, think again.