For a given weight, the standard material has roughly twice the warp strength of the high bias material. If you decide that you want a material in the 0.5 oz neighborhood for a tarp, for example, you could choose the standard 0.51 oz cuben (warp strength: 68 lb/in.) or the 0.51 oz high bias cuben (warp strength: 37 lb/in.)
Michael, I agree with you about using the high bias materials for tarps. Despite the lower warp strength of the high bias materials, it seems to me that it might prove more resistant to failure in high winds. My reasons for thinking this are a bit convoluted, and I have no engineering expertise, but I think it would be an interesting experiment (justifying the cost is another issue).