It'd work perfect for a OBW. OBW's do not have to have a LOT of different colours. More important is the pattern change across the fabric to create the kaleido interest.
As for the solid black areas, you do not need wall to wall (or should I say selvage to selvage) of colour on the fabric. The solid spaces won't even show once the triangles are cut up and hexes assembled. It will help give a bit of a break from the busy-ness of some of the other blocks, and the more black ones will be stunning as bits of the turquoise and yellow pop in for what I bet will become an elegant kaleido.
All that being said ... I'm like several of the others, and chances are I would not cut up the fabric, and would use it as a backing for a front made of coordinating colours/fabrics!