Hi, I have been watching OP for a while now and there has been one thing bugging me throughout the entire thing. This may have been asked before but I cant find any answers. Sea stone is meant to nullify devil fruit powers. Nets, cages and cuffs have been developed, so why doesn't anyone make sea stone weapons? Swords, bullets ect. Due to its "harder than diamond" strength, it would be ideal. Captain smoker is the only one in the entire thing who seems to use a sea stone weapon, and this raises another question why dosent it nullify his power?