first of all, there is no indication Ussop has it, second, if Ussop gets it that dosent mean Sanji should also get it just because Ussop has it. Thats just absurd, cringe and stupid. CoC dosent mean the character is strong. Sanjifans should stop with this "if x character has y haki then it should TOTALY also happen to Sanji because my headcannon demands it".
This is where you said it, IF even ussop manages to get it, you desperately want Sanji to also get it because the strongest characters in the verse had it...Not because there would be any reason at all for him to get it.