to get the dragonvoters on enels side:
enels bounty said by oda, if would be on grandline: 500 million
blackbeard: 0 (last known) 
Dont forget the Guragura no mi did nothig against logiausers. They crumbled, but without any injury. The only hope is the black hole, but against lighting with godly Mantra... have luck.
So, lemme get this straight.
You're comparing a non-existent bounty to another non-existent bounty
But alrighty, let's play that game.
Oda said, in response to a fan asking what Enels bounty would be if he descended to the grand line. Oda said that the bountyless Enel might end up with a bounty of 500 mil. But there would still be bigger fish:
"D: Question!! If God Enel were to descend to the Blue Sea, how much would his bounty be? Also, what would happen if he did that? Would he rule the Blue Sea? P.N. Gorozoro
O: I see. Interesting question. Knowing how tricky he would be to beat, I'd imagine he could reach as much as 500,000,000 Beli. Luffy was lucky to be rubber. But like Luffy said, there all sorts of even crazier guys down on the Blue Sea. Enel would NOT rule it. "
Now, it would be interesting if a fan asks for BB's current bounty, which he is bound to have by now. What exactly in your train of logic makes you think his bounty is not considerably higher than 500 mil? You cannot know.
Oh yeah, remember Ace? He was revealed to have a
550 mil bounty , higher than Enel's estimated bounty. And he got his fiery ass handed to him by BB even before he got the Gura Gura no Mi. A fruit he should now be able to wield better than he did at MF.
So, in short, the bounty tale does not hold the slightest bit of merit, I am afraid.
