I've talked to shops that have a torque plate for everything they bore and hone. In spite of the assumed difference aluminum makes, the consensus for this particular company is a steel torque plate is used on all blocks. We use a steel plate, ground flat
Would an aluminum plate make a real difference? Maybe. I really don't think it would be much, but one thing you can't argue. Where that video showing a Cummins block out of shape by squeezing with your hands is rather impressive. If only your hands will distort that much, what will all those bolts tightened to 150 ft lbs do?
The other thing I have been convinced is that you have to tighten up the block with the bolt type you intend to use. If you are using ARP's, install and tighten them up. If you are using stock head bolts, bolt the torque plate on with those. For those that say, "Yeah, but those TTY head bolts are 'use once only'. Well, my answer to that is, when a used bolt will no longer hold the torque plate correctly, replace them. They will work many times before they entirely stretch beyond use.