There was literally nothing about the boots except they have magnetism and can help you fly. The GLOVES let you interact with the light, but the boots were never given to have such effect. Glad to see you pulled that one out of your asses.
Given the fact that we literally see Sanji speed from below, and purposefully jump in front to block Kizaru (speed feat as he wasn't near them), he either had to be pretty confident he could deflect the attack or crazy enough determined to saving Bonney to try.
So will you give him this as a INT and CON stat move (knew he could block it, and did).
Or a WILL SAVE (had the determination to save others to try) and admit his strength of will is up there?