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The Queen is placed on a square where it is subject to attack by the White minor pieces. This gives White the possibility to develop those pieces with an attack, thereby gaining time. The sequences Nb1-c3-d5 and d2-d4 (or d2-d3) followed by Bc1-g5 will be possible in many variations.
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The Queen occupies the best square of the Black King's Knight. Either the Knight will be developed to one of the less effective squares e7 & h6, or the Queen will move a second time to make room for the Knight.
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It is too early to determine the best square for the Queen. Maybe the Queen will eventually find a good square on f6, maybe it won't. It is too early to tell. It might be better placed at a5 (after moving the c-Pawn) or at e7. It is more flexible to see a few more of White's moves before deciding where to develop to the Queen.
The move 2...Qe7 has similar drawbacks. On e7, it blocks the Bishop instead of the Knight, but Black will still have to take special measures to develop the dark squared Bishop.
After 2...Qf6, a sample variation is 3.Bc4 (3.Nc3 is also good) 3...Qg6 4.O-O (or 4.d3 Qxg2 5.Bxf7+ Kxf7 6.Rg1 Qh3 7.Ng5+) 4...Qxe4 5.Bxf7+ Kd8 6.Nxe5 Nf6 (6...Qxe5 7.Re1) 7.Re1 Qf5 8.Bg6 Qe6 (8...hxg6 9.Nf7 mate) 9.Nf7+, winning the Queen. Note how the Queen gets into trouble in the few side variations that we've indicated.
