One Piece fans have been waiting for Jinbe to join the Straw Hats since Luffy first visited Fishman Island. During the "Wano Country" arc, he finally became an official member of the crew and demonstrated his might as a former Warlord and the strongest Fishman. The Straw Hats' new bounties were revealed following the final battle of that arc, essentially portraying them as elite pirates. Each of the Straw Hat pirates is a formidable member of the Yonko crew. As is customary, Luffy and Zoro rank first and second.
However, Sanji, who has always had the crew's third-highest bounty, loses his position to Jinbe. Needless to say, despite having a bounty of over a billion berries, he is not hiding his disappointment at being below Zoro and Jinbe. Due to their monstrous strength and being the team's three strongest members, One Piece's Monster Trio has always consisted of Luffy, Zoro, and Sanji. Now that Jinbe is the Monster Trio's third-strongest member, the question of whether he is the new member arises.
Why Is Jinbe's Bounty Greater Than Sanji's?
A bounty isn't a foolproof method of measuring someone's strength in One Piece. There are several instances in the series where pirates defeat those who have far higher bounties than them. The primary example is when Luffy -- a pirate with 500 million berries before the "Whole Cake Island" arc -- manages to defeat Kakakuri, a high-ranking crew member of a Yonko with a bounty of more than 1 billion berries.
Apart from one's strength, a bounty is a numerical value to measure up the threat the criminal possesses. Jinbe is not only a former Warlord, but his contribution to the Summit War is undeniable. He manages to save Luffy, someone Akainu desperately wants to kill. Therefore, Jinbe's earlier reputation and the fact that he has joined the Straw Hat pirates -- who have openly declared war against the World Government -- make him a serious threat to those on the side of the law.
Why Jinbe Didn't Replace Sanji in the Monster Trio of One Piece
Jinbe now has a bounty of 1.1 billion while Sanji stands at 1.032 billion. Therefore, the difference in the amount is not significant to specify who is the stronger of the two. For now, at least, they seem to be on a near-equal footing. Moreover, looking back at the "Wano Country" arc, Sanji's contribution was actually more significant as compared to Jinbe's.
While Jinbe fights against Who's Who (a Tobi Roppo member), Sanji defeats Queen, the second-strongest pirate in Kaido's crew. Furthermore, One Piece fans have been used to seeing Sanji as part of the Monster Trio for more than 25 years. Therefore, it wouldn't be comfortable to watch someone else there, even if Jinbe is a fan-favorite character. Sanji retains his position in the Monster Trio and, seeing how he is awakening his genetic mutations, it's not farfetched to think he will surpass Jinbe in the series' Final Saga.