Amarande: <aw1988> 7 ... Kf8 does appear better from some strategical points, in particular the development of the Black Rooks.
After 7 ... Kd8, the development of Black's a8-Rook is heavily hindered, as it will take at least two more non-developing moves (c6 and Kc7, at the least) to usefully extricate this piece without causing additional interference.
On the other hand, after 7 ... Kf8, the Rook can go straight to the open e-file as soon as the Bishop is developed. Often, Kf8 in such situations can be bad, because it hinders the h8-rook, but as the check that forces Black's King to move opens the g-file for Black this is not really an issue here.
The game could continue (after 7 ... Kf8) 8 Nd2 Qe5 9 Nf3 Qxg7 10 Bxc5+ Nge7 11 Bc4 d6 12 Be3 Rg8, with an interesting game. (Note that swiping the g-pawn at move 12 would be highly dangerous, on account of 13 Bh6+ Ke8 14 Rg1 Qh3 15 Bxf7+ etc. with a withering attack)