Why is c4 a better move in this position? The computer analysis on a game I played tells me that in the following position, White should have played c4 instead of e5:

[fen "r3qrk1/pppb1ppp/1nn1p3/6B1/3PP3/P1P2N2/4BPPP/R2Q1RK1 w - - 0 1"]


The engine (Stockfish 10 from Lichess.org) tells me that c4 would have given White an advantage of +2.2, compared to +0.9 with e5, so it's quite a difference.

I don't see any immediate tactical win with c4, and while it would give White some extra space, so does e5. Furthermore, e5 results in a pawn structure that points to Black's king (I've heard that you should attack in the direction your pawn structure points to), plus covers f6 in case Black wants to move his f pawn there. c4 also results in three pawns being aligned on the 4th rank, which I am not very comfortable with.
White intends to play c5, which will gain space on the queenside and severely cramp black's position (The b6 knight has no good square).

On the other hand, e5 weakens white's control over d5 and f5 (e.g. Black can then go ...Ne7-f5).  Black could also take advantage of the weak c4 and d5 squares with ...Na5 and ...Bc6.  Keeping the pawn on e4 seems better.  It also keeps the h2-b8 diagonal open for white's unopposed dark-squared bishop.  Preventing black from playing f6 does not seem very important to me.

By advancing c3-c4, the c4 square also becomes less of a weakness because it can now be covered from the rear with Qc2 or Rc1, which is impossible with a pawn on c3.

Slightly weakening d4 is not a big deal, because it's easier for white to defend d4 than it is for black to attack it, since white has a big space advantage and a dark squared bishop, while black is quite cramped.