Certainly not a move I would play. 1.e3 is my own usual choice, but there are good alternatives.

I used to play 4. Bg5 – The Leningrad Variation but now play 4. e3

"Castle early and often" Em Lasker.

This could in fact have been played a move earlier, to induce the exchange on c3. The coubled pawn on c3 is not a weakness exactly, but is a bit inconvenient should White wish to advance on the Q-side or centre.

I would have been very tempted to play 7...f5 in the hope that White would play 8.f3 to attack the knight and force a decision. Then comes 8...Qh4ch(!?) 9.g3 Nxg3 10.hxg3 Qxh1, with a very unclear, wild-looking position. GM Mikhail Tal was exploring a line something like this at about the time of his first World championship match in 1960. I see no examples of this line on the GK World database, but there are 5 examples on the 'in-house' database, with 4/5 success rate for Black.

This looks as though it is going a little bit wrong for Black.

Now White seems to have gained a solid extra pawn, and a mobile, well-advance Q-side majority into the bargain. Though he is just a little bit behind in development, I much favour White's chances at this point.