You can't mine SHA-256 coins with GPUs
Wrong.
Care to elaborate? This isn't 2011 or 2012 anymore. You can't even mine with those USB blue or red furies or even Antminer U1's anymore due to difficulty and network hashrate.
You can mine with GPUs, you can mine with blue and red furies and you can mine with Antminer U1s, they won't be profitable but you can certainly mine with them