sanji had a clash with doflamingo not a fight and he got wrecked if the marines saw that they wouldn't consider sanji a threat.
But killer got praise for kaido himself and will be one of SNs responsible for his defeat as per oden's prophecy
So?
Doflamingo "praised" Sanji as well. So what?
Kaido praised the Flying 6.
Kaido protected Jack and praised the Dukes.
Jack is said to have been handpicked by Kaido himself.
Big deal.
Killer did 2 things on the roof:
Use the sonic attack to get 1 hit on Kaido, and then he got immediately zapped by Big Mom. The sonic thing did, at best, a scabbard level of damage. There was nothing special about it, aside visual effect. And then he stalled Napoleon.
That's it. Why the fuck would he suddenly get a 1B+ for that and defeating some supernova with a bounty lower than most of the Flying 6?
The only way for his bounty to get a significant increase and break the 1B mark, is due to his association with Kidd, who will defeat Big Mom with Law's help.