Because it's not esterified, and thus would have the same or very similar half-life to the oral dbol, and would need to be injected very often, ideally 3x/day. It would avoid first pass metabolism, and therefore any given dose might be slightly more effective, but the whole purpose of 17α-alkylation is to eliminate first pass losses, so I think this effect would be minimal. It would however still ultimately be metabolized by the liver, so it would still have the same negative effects on the liver.
Plus it would use up valuable syringe space that could better be used with some test.