You will never see PAW in structural welding, but I think you don't mean just strictly structural standards.
gtaw and weldstan are correct, you tend to see it mechanized only. The difficulty is the extra quality of fit-up demanded, particularly with the keyhole plasma technique.
I did however once review some SS welding procedures for a Belgian pressure vessel maker and I must say I was impressed. The shell joints had a kind of hybrid design, with a fairly substantial land and zero root gap. The root was done with plasma and the balance (where there was a V-bevel) with a more conventional process, IIRC GMAW.
"Everyone is entitled to their own opinions, but they are not entitled to their own facts."