Nerwal: <why was qd2 played by white? It blocks the black bishop and isn't it against opening principles?>
White has to consider :
* the dark-squared bishop has no interesting prospect on the c1/h6 diagonal : the only good square is g5, but this would ultimately lead to trades (which are in Black's favor).
* other squares than d2 for the white queen have drawbacks (e.g. on d3 the queen can be hit by ♘b4 or ♘e5)
* the c4 pawn can be sometimes attacked by ♗e6 or ♘e5; White wants to play ♘d5 only under favourable conditions and would prefer to develop with g3 and ♗g2 rather than e3 and Be2 which is less active, so b3 will have to be played.
All this suggests than the best setup for White is ♕d2, b3, g3, ♗g2 and then either ♗b2 or ♗a3 (after Black has played c6, in order to put pressure on d6)
There are other openings where White plays this odd-looking ♕d2 for similar reasons (e.g. : 1. e4 c5 2. ♘f3 d6 3. d4 cxd4 4. ♕xd4 ♗d7!? 5. c4 ♘c6 6. ♕d2!).
<and what happens if black develops normally say Nf6 and Be7?>
Nothing special but this setup is passive. White has a space advantage and a very sound pawn structure, similar to some lines of the Philidor or the Budapest gambit. Black would like to exchange some pieces to lessen the problem of lack of space, but fianchettoed bishops make trades harder to achieve. A good positional White player will torture Black endlessly in this type of position.
There is a reason why the Morphy lines of the Spanish have become overwhelmingly popular over the Steinitz lines with d6, ♗e7 and exd4.