Double Uppercut: not so interesting?

Why would you Backspin -> Fist? Backspin -> SSK if anything. And anyway, I'm referring to the points you gain from maxing it versus the points you gain from maxing DU.

I was just referring to the way Loose trained. I've not been able to use bs efficiently seeing as it's level 1, so I thought that's how.
But yeah, I guess you would SSK after wards.

But wouldn't corkscrew kind of manage the same thing? I guess it would somewhat weaker, but still, does that make BSB priority skill?