Two of my pic(k)s weren't even road cars:
The explanation is rather simple.
Fangio in a Mercedes GP car, driving in shirtsleeves and trousers is the classic image of racing before Nomex, sponsorship stickers plastered on cars with wings.
The C-111 showed that Mercedes was still an engineering driven company that still knew how to design "knock your socks off" visually appealing cars. Sacco had his "A-Game" when he came up with that design.
The 600 Pullman is just so beautiful in it's sheer size and audacity.