Good for heavy AND light winds?
A roller furling jib should only be used partially furled if the sailmaker has strengthed the sail with cloth reinforcement at the furling point. Sailmakers will only reiinforce up to 30% of the sail size, as furling the sail more than that produces an aerodynamic mess. Should one attempt to use a roller-furled sail as a storm jib, the attempt would likely be brief as the forces would quickly shred the sail, small area or not. Storm jibs are made out of fabric up to twice the weight/strength of a normal sail, and more heavily reinforced.