Scrambling 2NT

The scrambling 2NT bid is used after partner makes a takeout double at the two level, and you hold two four 
card suits. 

E.g. 
(1S)-p-(2S)-x; p- ??? and you hold: 
S: Kxx/ H: Qxxx/ D: Jxxx/ C: xx. 
If you bid hearts, you could wind up in a 4-3 fit (and the same with bidding diamonds). 
Why guess? If you bid 2NT as a scramble, partner can bid his four card suits up the line. 
With S: xx/ H: Kxxx/ D: AKx/ C: QJxx , partner bids 3C over which you bid 3D to deny holding four clubs and then partner bids 3H to 
show that suit. 

Why play this convention? 

1. First, you and your partner may make more aggressive doubles knowing that you can find your 4-4 fits safely.
2. Second, if partner does not go thru Scrambling 2NT, then the doubler will know that the suit is a five 
   card or longer suit. 
3. Third, what else is 2NT supposed to mean? Natural? Why not just pass their doubled bid then?