Shadowdancer chain backstabs vs. just attacking

So the Shadowdancer may Hide in Shadows even while being observed by enemies, but their backstab multiplier is reduced:

Levels 1-8: 2x
Level 9+: 3x

It takes a round (6 seconds) to stealth before you can attack again, doesn't it? So isn't this:

Round 1: backstab for double damage
Round 2: stealth
Round 3: backstab for double damage
Round 4: stealth

The same as this:

Round 1: attack
Round 2: attack
Round 3: attack
Round 4: attack

?

I recognize that hiding in plain sight can be used defensively, too. Though it can be dispelled by something like True Seeing, can't it? Can some enemies see through it?