Strange Looking Move

I was going through a game today between Mongredian Vs Morphy from the Evan's Gambit opening, when the computer suggested a best continuation that made no sense to me.

I thought this strange so I looked in the ~Games Explorer and found that this move has been played 67 times before from master games in the chess.com database. Granted it is not very popular but it is still played more than I would have thought:

Ba5 623, Be7 255, Bc5 237, Bd6 67, Bf8 5.

Anybody have any suggestions why Bd6 is considered a good move here? To my eyes it prevents movement of the d pawn, doesn't allow free movement of the Bishop and generally cramps Black's position, so why is it considered Black's best move?

Thanks.

Bd6 has been played in various variations of open games (Four Knights, Ruy Lopez). The idea is to continue development with Nf6, O-O, Re8, Bf8, and Black has the option to push d5 in one go.

If White plays d4, Black has to protect e5. The usual move is d6 but if Black is going for the aforementioned development scheme he may save a tempo with playing Bd6.

I doubt that Bd6 is good in the Evans because White can play Qb3, disrupting Black's development plan, and the Bd6 looks rather stupid.

Thanks, yes that would seem to make some sort of sense now. It just looks so awkward.