Advance French- 4.Nc6 vs Ne7?

I recently took up studying the french and i was analyzing a game between Mikhail Botvinnik and Leonard William Barden.. I noticed in the game Mikhail plays the move 4.Ne7 and it was quite weird to me because I know the most popular and liked(engine wise) move is Nc6. Can someone explain the idea behind the move?

On first glance, it looks like it prepares an early nf5 to put pressure on d4 combined with nbc6, however it also allows an early 5. bd3 which is always a good move for white if available in the French, and the threats of taking on d4 are easily blunted. 5. bd3 allows white to have an ever so slightly better position but like most advance French positions, it'll be a relatively balanced position for both sides. 

This variation shows one of the ideas behind early Ne7.

10. c4 just looks like a mistake; white is probably better up until that point

That is a very interesting variation.. It seems to solve the french bishop problem but at the same time i feel like black is behind in development.(moved both knights twice)