One of the original reviewers in 1964 wrote that the film only really came alive for him when Grayson was onscreen.
It really was her big Hollywood moment. Thankfully for DS fans, she was less than thrilled with Hollywood (she had lived there back in the 1940s and I think the whole scene left a bad taste in her mouth--read R. J. Jamison's fascinating book, "Grayson Hall: a hard act to follow" for MORE).
Had Grayson really embraced a Hollywood career, she wouldn't have been available for work on DS and so...
G.