Playing 54, to split or not?

Last time I promised a shorter analysis, so here it is.
Today we'll discuss only one problem, also from the opening phase of the game, but it is regularly misplayed.

I encourage you to write your opinions about positions, questions about my analysis, etc.
By writing your opinion before seeing analysis you will sharpen your game; posting questions about analysis will help me to know on what should I concentrate while writing, where to put more or less effort in explanation, etc.

So here we go: