When presented by themselves, yes. When there is some pretext leading me to the point that I want to click a big shiny "download"/"sign up"/"take a tour" butto

When presented by themselves, yes. When there is some pretext leading me to the point that I want to click a big shiny "download"/"sign up"/"take a tour" button -- and then POOF, it's right there under my mouse -- I think that is sometimes helpful.