My idea:
Goddard(sp) wanked over american film, bogart et al, but felt guilty and recreated it- or alluded to it subtly, or almost mocked it.
Vadim loved american film from the gut, he made films with tits and ass and with pleasure. with american actresses not as a way to analyze but as a way to say thank you.

compare how Vadim uses Fonda in Barberlla- as an english speaking sex kitten as a blonde bombshell as the authentic version ( ie only americans were blonde bombshells) of bardot ( in fact he recreated And God Created Women in 1979 with DeMornay) with how Goddard uses Seberg (as a francophone, as one who is masculinzed, as one who talks instead of fucks, who rejected hollywood)