Stage Fright: Why is this film so important?

SPOILERS

I think Stage Fright is a great film, because of the strong performances from Alistair Sim, Jane Wyman, and Michael Wilding.

Just like Hitchcock's Suspicion, Stage Fright is a movie that goes "generally" in Point of View of Eve Gill (Jane Wyman) and sometimes her father Commodore Gill (Alistair Sim).

Umbrella is an important subject in Hitchcock pictures. In Stage Fright, we see Michael Wilding bringing an umbrella right before the romantic car scene. In Psycho, We see Norman Bates bringing an umbrella for Marion Crane (Janet Leigh).

The MacGuffin in Stage Fright is Doris Tinsdale.

In the Car Scene, Michael Wilding (Inspector Wilfred Smith) tells Eve Gill that he and police were looking for Doris Tinsdale. Only the audience, Eve Gill, and her father know that Doris Tinsdale doesn't exist. Doris Tinsdale is the name Eve Gill used when she started working for Charlotte Innwood (Marlene Dietrich).

This was later used in North by Northwest.

Its just like "George Kaplan" in North by Northwest. And George Kaplan is one of the MacGuffins in North by Northwest.

And I do like the plot twists especially when Smith (Michael Wilding) tells Gill (Alistair Sim) that Jonathan (Richard Todd) was acquitted for an earlier murder when he claimed that he killed in self-defense. In the middle of the film, Jonathan sneaks into theater to see Charlotte (Marlene Dietrich). That scene also surprised me.