If White exchanges Bs on f5, Black castles long and obtains good attacking chances on the half-open g-file. Ne1 is clever, for if Black now exchanges Bs on d3, then the White N comes to d3 and thence to e5 or c5.
Black has failed to equalize and is saddled with permanent weakness in the centre. His only hope is to get some counter-play on the K-side.
White can now pile up three heavy pieces on the e-file ("Alekhine's Artillery", from a famous game against Nimzovitch), paralyzing Black's pieces in defence of the e-pawn, and then advance his Q-side majority.
24... Rd8e8 25. Qe4e6
I was expecting Ra1-e1 here; Black could not hold the e7 pawn with ... Rh7 (immediately); White could re-locate the Q, for example to d4 or f5, and then paralyze the Black position with Re6.