AMEN to that, Jamie! Words of wisdom from the master.
We use copper because it works good. It's actually a lot more agressive than antler and is not fussy about how you set up your platforms, usually. Everything has to be perfect with antler.
The idea that hard metals send dangerous shock waves through the stone is kinda funny to me. A hammerstone, like quartz, is a lot harder than metal and "shocks" the stone quite a bit more than metal. Why is there no warning against using hammerstones? It's because not many people have actually tried to knap with steel, bronze, brass, aluminum, etc. Mild steel is actually very similar to copper but it's not used very often because it's slightly more aggressive. I haven't tried bronze or brass but I would if I had some.
Ishi had at least one steel pressure flaker in his tool kit, if I remember right.