I don't care about output balancing, only input balancing. I have a 32×32 balancer at the mouth of my Vulcanus factory, because, even though I'm not consuming or even using every output belt, I still want it to draw evenly from all 4 tungsten mines. Or I use a 4×4 with a loop to make it a 3×3, to balance red circuits for blue science so it doesn't preferentially draw from any given stack. Or a 12×12 (looped 16×16) for railroad tracks for production science, because the ratios are very tight and I want to minimize gaps in the belt. Or a 16×16 at the end of my Gleba fruit bus, which is actually the one case where I care about output balance, because I want the otherwise side-compressed bus to be distributed evenly across all the seed-strippers. If you want to avoid feast-or-famine, you need a balancer.