Precedent is a social convention; there is no rule that judges have to follow precedent.
And the CAFC chooses which precedents it likes to follow however it likes. Supreme Court precedents have no special power over the CAFC. Just look at how Benson is treated by State Street Bank or Alappat.
Like all law, yes, case law is a social convention, but there most certainly is within US case law, quite specific rules requiring judges to file precedent and defining which precedent they must follow (binding precedent) and which they are not required to follow.
