IMO BB30 (and other press-fit bottom brackets) are all a significant downgrade from threaded BBs. Because the disadvantages are real, too. The parts of a bicycle that are probably subject to the greatest stresses and forces are only pressed together.

And it certainly is marketed - because it's all about lower production costs for manufacturers. So they figured out some things that it can do slightly better than standard threaded bottom brackets. Not that standard bottom brackets actually perform unacceptably in those regards. Kinda like saying that a pair of pants that are strong enough to tow a cruise liner are better than a pair of pants that would rip. True, but so what? It's better at something that doesn't really make any difference.