If I'm not mistaken, this is the third time a "jazz musician" has won the Pulitzer. Wynton Marsalis won in 1997 for his (in my opinion) rather workman-like Blood on the Fields, a retelling through music of the African-American experience, which pales in comparison to the similarly themed "Roots and Folklore" by John Carter, which I have praised in this space on several occasions.
Ornette Coleman won for his concert recording Sound Grammar, which, as good as it is, seemed a bit like it was awarded not for the work itself, but in recognition of Ornette's body of work, sort of like when Paul Newman won his Oscar for the Color of Money.
The committee seems to not quite be able to recognize this as a "composition", however. The official site refers to In for a Penny, In for a Pound as a recording, citing the album release date in the spot where it usually lists a work's premiere. I would love to see the Village Vanguard, where I heard Threadgill's group Zooid perform this piece in August 2014, join the ranks of Carnegie and Symphony Halls, or Lincoln or Kennedy Centers as the site of a Pulitzer winner's premiere.