I fail to see minor advantages


That is a position from the opening. You have already traded queens and a pair of knights. I don't know the particular opening but here black already has an easily visible weakness-- a backwards d pawn. White has three pieces available to attack the d pawn and black has only 2 available for its defense.
If you run the engine, it shows a 1.89 advantage for Bf4 and gives a very clear line on how it would have won the pawn.