But then again, my phone's GPU is infinitely more powerful at 3D rasterization than the entire Bitcoin network (because the Bitcoin network can't do 3D rasterization).
My analogy might be a bit convoluted, but my point is that - as you mention - that we're comparing oranges to apples. We're comparing a general-purpose computer to doing a SHA256 hash.
[1] At least, that's what they tell me. I suppose it depends what you define as power.