I have also done it. None of the things you mentioned predict success. In fact, very little aside from basic hygiene is likely to predict success, which is what renders these purportedly meritocratic hiring processes so out of touch with reality.
If this data is present (data showing that present hiring methodologies don't predict successful business outcomes), do you have data showing that hiring people who need jobs is any better? We /are/ different from each other -- as an example so obvious it borders on the ridiculous, people who have been programming for ten years will be much faster at it than people who haven't. At what point do you draw the line to state that people stop being different? If so, what data did you use to draw that line?
[1] http://blog.alinelerner.com/resumes-suck-heres-the-data/