Sure, it's not totally necessary. Just speaking my opinion :) The way I see it is that if I can get more control for the trivial amount of effort needed to use a cage, that's a huge plus for me. I've seen the technique you mention. Honestly? I let skewing happen and I'm happy with the results. I don't waste time with…
I've baked some complex (ish) meshes cage less in SP. Never really a problem as I usually bake synced. Also, I've seen an Interesting technique recently of setting up a graph in SD to blend averaged/non-averaged bakes to get the best of hard edges and non-skewed details from the respective maps.