Yeah, I agree. It's a big time saver. I don't know how this isn't the default, because it makes a big difference in how fast you can get a model done. I'm sure most will agree that you tend to switch between vertex, edge, and face modes waaayy more often than you would switch between layers during the course of a modelling session. But it's still a testimony to the power of Blender that we can customize it to our workflow in such a way. Blender is amazing.