Tubes vs. Grubs in current

Ok, Teachers, your lowly pupil has a question. Reading the Jan.
Bassmaster, I find an article on winter river fishing. The article
brings up baits and presentations, mentioning that when using tubes, you
want the bait to move WITH the current. This I understand, because bass
normally are facing the current, expecting the current to wash food
their way. But when discussing grubs... here, I'll just quote:

"Grubs - River anglers find action-tail grubs more productive in a
slightly off-color river. A curl-tail or thumper tail generates water
movement that may help bass zero in on the bait. Retrieve steadily with
current, at angles to current, or even upstream. This sets grub
presentations apart from the 'with current' presentation of tubes"

Ok, guys and gals, what's the diff? both baits simulate live bait. If
it's just the "thump" of tail movement, couldn't you use a rattle in a
tube for the same effect? I don't understand why tubes MUST flow with
current, while grubs don't. Does this mean that spinners do just as well
upstream as down? Or is it just a poorly written article?

Henry

"Right now I'm having amnesia and deja vu at the same time.
I think I've forgotten this before." -- Stephen Wright