A hundred and forty four degrees is two fifths of the circle. The biquintile is therefore the quintile's partner in the fifth harmonic, standing to it as the sesqui-quadrate stands to the semi-square, and it comes from the same source: Kepler's attempt to derive aspects from the regular figures inscribable in a circle and from the musical ratios those figures express.
It is the least used aspect in common circulation, and the reasons are practical. Five does not divide twelve, so it cannot be found by sign and has no traditional standing to inherit. Its orb is narrow, commonly one to two degrees, so it appears in few charts. And it sits close enough to the trine at a hundred and twenty degrees and to the opposition at a hundred and eighty that a reader working with generous orbs elsewhere will often have accounted for the same pair of planets already.
What is said about it follows from the quintile rather than from anything observed independently: facility, pattern-making, a talent that shows as style. Writers in the harmonic school treat the fifth harmonic as a whole and read the quintile and biquintile together rather than separately, which is the more defensible approach, since the case for either rests on the case for the division by five. The geometry is exact and can be stated without qualification. The meaning is an inference from number symbolism, roughly four centuries old at most, and it should be presented that way rather than as inherited doctrine.