it is planned and intended for using on other fabrics but it is just not there as of yet. we have seen pretty nice results on the light and white poly materials but the darks are just not there.
i will say that you have to be prepared that the pop of the colors is just not as good on the poly material as it is on cotton or even 50/50.
Seeing that i run a Kornit, i find that printing on poly the colour is not as vibrant as cotton. and if you do print on black, the white ink does not last very long on the garment, it will start to fall off.