To be fair, Airport grade Aluminum will be strong enough (for 6.1") to avoid bend gate (due to flat edge vs curve)
To be fair, Airport grade Aluminum will be RF good enough for sub Ghz pseudo 5G.
With that being said, Airport grade Aluminum CAN BE EXPENSIVE if Apple choose to use same process with iPhone 5. It will be more expensive than iPhone 5 due to Hardness of Airport grade aluminum, hence CNC Grind Bit life cycle shrink.
Airport grade Aluminum IS NOT CHEAP, BUT IT IS READILY AVAILABLE
Check video from 4:50
With that being said, there is no CHAMFERED edge on this iPhone 12 Pro.