Reason(s) to play 5. Nf3 in the stonewall dutch opening? I have heard that it is a good idea for white to trade dark-squared bishops because blacks pawns often end up on light squares leaving the dark squares vulnerable.  In the scenario below, it seems 5. Nh3 is white's best move for reasons I will explain below, but are there any good reasons why white would choose 5. Nf3 over 5. Nh3

[FEN ""]
1. d4 f5 2. g3 Nf6 3. Bg2 e6 4. c4 d5 5. Nf3 (5. Nh3) c6


If white does in fact play 5. Nf3 and play continues with 5...c6 6. O-O Bd6, then if white's Knight were on h3 instead of f3, white could easily prepare the move Bf4 without worrying about getting a damaged pawn structure.  With 5. Nf3 c6 6. O-O Bd6, white's best move is b3 aiming to exchange dark squared bishops with Ba3, but black's Qd7 stops the dark squared bishop exchange for sometime.

Given the above, if white isntead decides to play 5. Nh3, white is preparing Bf4 for the exchange of the dark squared bishops and avoids the battery of the Bishop on d6 and the Queen on d7.

Given that 5. Nh3 has known as long as the stonewall formation has been known and masters of the past have played it frequently, so why is 5. Nf3 more popular when it actually seems inferior to 5. Nh3.  Is it because 5. Nf3 just seems like a more natural move or has a more natural feel to it?  Are there any other reasons to play 5. Nf3 over 5. Nh3?
A couple thoughts:


After Bxf4, taking gxf4 is acceptable.  The g-file is open, black's ideas of g5 are prevented, you have a lock on e5, and can fix the pawn structure with f3+e4.
After a g5-g4 push, h4 is often a better square for the knight than f4, to stop h5-h4.
f3 points at e5, a better square than f4.  f4 is vulnerable to an e5 push, and the e6 pawn is rarely weak.