Bed is a far more conservative piece than Duchamp's, which questioned what could be permitted as art. Emin came along after that battle had largely already been won. Her piece is 'allowed' because of the earlier acceptance of his work, and that of Warhol, etc.) but uses it to return to a far more romantic view of the artist-as-social-outsider.
As such I always think that Bed has more in common with Van Gogh's (admittedly superior) Chair.
