Anyhow I feel like we're drifting off topic.
To bring us somewhat back
on topic...
The bounty system is interesting because of what it encourages.
You're right in that it was not the most internally consistent metric ever developed, however
@Ford Prefect's right in that it is probably the best that's been seen to date.
Numbers Getting Bigger is something people like and Oda made the trope more substantial because it represents not only strength, but impact: the government (your enemy) respects you this much and is willing to shell out exactly this much for your corpse. When the Straw Hats squee/quail in horror at their rising bounties, it's not an acknowledgement of 'my ATK stat is this much more potent' but rather 'WOW WE JUST DID A REALLY BIG THING THERE.'
The fact is the bounty system encourages a certain sort of storytelling. You don't get wrapped up in training shenanigans because it's not strength that gets measured it's plot: what you do makes your bounty go up. When Goku's PL rises to over 9000 all that means is that he's a lot stronger than he was at PL 4000. When Luffy rescues Robin and everyone was like holy shit, the WG gave them all bounties and it was a very satisfying shounen-esque resolution. It has impact, it has style and it puts a period to what tends to be a really notable arc.
For example, other than the over 9000 bit that was inexplicably pounded into the internet's collective psyche, I don't remember or care what Goku's PL was at any point. I think he may have hit a million when he went SSJ for the first time, but I'm not sure - it could've been ten million or a hundred million, but in the end it's all just numbers.
But you bet your ass I remember when Luffy's bounty first hit 100 million (he'd just defeated Crocodile) and when it hit 300 million (rescued Robin). That is one
hell of a trick. People like Numbers Going Up but no one actually cares about them. Oda associates those numbers with his arcs and you go:
holy shit!
When other people get to where the Straw Hats are and have similar bounties you know, right off the bat, that they have had adventures and did things that are similar to what the Straw Hats did. It's a shorthand for 'a
lot of shit went down that you didn't see and these are notable people'.
Oda's bounties are half-PL, half-reputation. That they don't always intersect perfectly is a consequence of the medium and the needs of that medium: sometimes you need to hype people up, and sometimes it's obvious that the PL mechanic of a series that was planned to last five years could not really survive one that went on for 10, then 15, then 20 (One Piece is about that old, right? It's not just me?) and the inevitable inflation that accompanies a setting where one of the main points is that the villains you're facing couldn't hack it out there in the 'real' world.
But what's best about the One Piece bounty system is what gets left unsaid. Certain people just never get their PL measured. We never find out what Whitebeard's bounty was (nothing would suffice - it would have cheapened his reputation) or Roger or even Big Mom whom the Straw Hats are fighting right this second. When an enemy gets announced as having X bounty, it either serves to hype up their fight, save time, or go 'this guy will be notable later on, remember them'. But when someone
doesn't have a bounty it's because Oda mentioned them three hundred chapters ago and they don't
need a bounty.
I think, ultimately, that's the problem with a system that measures everything and gives it a number. Once you introduce that you can't
stop it from taking over everything else. The bounty system, on the other hand, can be carefully shooed away when you need to be a little more serious or reintroduced for comedy and other such things.
