You're ignoring things that contradict your view.
Bounty can only allow you to make reasonable assumptions about a person. It can't tell you anything factually other than they've committed crimes and been involved in enough incidents to acquire x-amount of bounty.
If you're a home owner looking to make some renovations.
- You have the option of 2 carpenters, one is 35 years old, the other is 50.
It is reasonable to ASSUME the 50 year old carpenter is better skilled than the 35 years old, but it DOESN'T mean it is true.
- The 35 year old might actually be much more skilled and even more experienced than the 50 year old.
Even if you guess the 50 year old is more skilled than the 35, you're not illogical for making that assumption, but end of the day, the quality speaks for itself and the 35 year old just happens to be better.
A bounty is no different, it allows you to make good fair suggestions about people, but suggestions and first impressions are not facts. A 1 billion beri bounty can have you suggest x person has Armament Haki, King's Haki, Future sight, but it doesn't mean they do. It doesn't even mean they're strong. Robin's 900m bounty is almost as meaningless as Hancock's.
Someone who looks good, dresses well and smells good for an interview can suggest you're dealing with a smart person. Doesn't mean they're smart.
Bounties can only allow you to make impressions of people, but those impressions are not facts, they're assumptions.
Bege and Luffy referencing Katakuri's bounty doesn't mean we can say since Katakuri was said to have Future Sight at 1.1 billion, then Zoro and Sanji also have Future Sight.
Bounty can suggest strength, but it may also not suggest strength.
In fact, Jimbei has a higher bounty than Katakuri, but I doubt Jimbei is even stronger than Katakuri.
Like I said,:
- A bounty only goes up after a crime or incident. Your bounty never goes up because you got stronger, it only goes up because you committed a crime.
Jimbei's bounty is 1.1 billion, because he was part of a crew that defeated 2 Emperors.
- Katakuri probably still defeats Jimbei nonetheless. Bounty is not strength level, it only allows you to assume.
Robin's bounty is 930m? Smoothie is 932m.
- Robin is not stronger than Cracker with 800m even with her 930m bounty.
- In fact, she's not stronger than Perospero who is as strong as SuLong Inuarashi and Nekomamushi, yet Perospero has a 700m bounty.
High bounty can mean strong the same way being old can mean you're smart and experience, but it's only assumption.
- Bounty only has meaning in context of the crime.
- Robin had a bounty of 79 million at the age of 8
Hancock had a bounty of 80 million at the age of 18 whilst being the Queen of Amazon Lily, Haki user and considered strong enough to be a Warlord.
Is 8 year old robin as strong as 18 year old Hancock? Obviously, she's not. Bounty doesn't really mean strength, it can suggest someone is strong but suggestions/assumptions don't mean it is true.
Even if you make the argument, the best you can do with a bounty is give the benefit of the doubt they're strong, but you can't say they're stronger.
Someone with a 500m bounty might be stronger than someone with 1.5 billion. There's a lot of reasons why someone with 500m bounty is sttronger, but has a lesser bounty.
Hancock's bounty doesn't mean much other than she's committed enough to get that bounty, and that's really it.
It's actually impossible to understand bounty without knowing what the person did to get it, and what it suggests about said person. Robin got a 80m bounty for reading Poneglyph and Hancock got her 80m bounty for going on 1 voyage... bounties of equal value don't make 2 people equal.
It only means what they did was dangerous enough to acquire said value from the WG.