The "Lose Your Powers" Mission is basically a stall tactic, but there is more to it than that.
I would theorise that the reason why such missions occur in games is because of demos. The demo of a game is traditionally the first mission, and with such demos developers often want to impress people with all the abilities you get later in the game. So they can either spoil a sequence later in the game, or they can make you get all those abilities in the opening sequence, then find some excuse to lose them.
Neither is a great option, but quite frankly, I think I'm speaking for most of the gaming community when I say that I'd rather there be no demo at all than suffering through this crap.
And if not that, then just spoil a later fight sequence with the demo. No one usually minds if it's just gameplay getting spoiled, since that's partly in control of the player anyway. That also means taking it light on cutscenes, though, which isn't in the developer's best advertising interests. Considering that, I don't think the tradition of such missions will die anytime soon, sadly.
DrunkWithPower said:
It gets old really quickly. God Of War and Assassins Creed are the main I thought of
You said it first.
Assassin's Creed wasted everyone's time by teasing us with full abilities then taking them away. What really annoyed me about it, personally, was that they weren't even all abilities that required the items you lost. Altair just "forgets" them because he's gone down in rank. I found that really lame.
Metroid Prime has such a mission, and it wasn't so unrealistic in how you lose powers, but it was weird and felt artificial getting new powers before you restored all the old ones.