1) The audience is tiny compared to Youtube. 2) The userbase is much more professional. If you want to learn how to shoot a documentary, put stuff on Vimeo. If you want to talk into your webcam, Youtube is the place. The only people sharing Vimeo content are those that actually care about the cinematography and quality of image, while Youtube is the defacto.
I've noticed that Vimeo tends to feature a lot of the independent movies and documentaries that get featured at film festivals. So yeah, I agree, maybe Faith should consider her motivations behind this and whether video is the medium that will best represent her story. In that line of thought, xofaith are you familiar with Hyperbole and a half? Allie uses comics to talk about her story and the issues that have affected her (depression especially). Don't feel you're limited to just one medium for yours :)