If he just takes attacks sure, but Cracker's base form is glasscanon compared to Jack's. Most one piece characters would take damage from lethal sword attacks outside of exceptions like Kaido or Big Mom and Cracker even more due to having lower durability/endurance compared to other people on his level. Right after this, Jack could clash equally with Asura, which is a greater feat than Cracker who relied more on his biscuits. Now, Cracker's biscuits are obviously part of his power, but the point is Jack's base form is stronger than Cracker's base form. He'd need his biscuits to keep him at bay and Jack also has his zoan form, and Jack's zoan form durability >>>>> Base Jack's durability, but has lower mobility and combat speed. However hybrid form should create a balance between both