Because it answers the question whether replanting the seeds of a patented GMO plant counts as a permissible use under the patent exhaustion doctrine or whether

Because it answers the question whether replanting the seeds of a patented GMO plant counts as a permissible use under the patent exhaustion doctrine or whether it's patent infringement. Absent this ruling, a court might have concluded that harvesting and replanting was such a typical use of a plant that it could not constitute patent infringement. (Also, what's the clear-cut contract situation? I don't think there is one in this case.)