I don't understand (the benefit of) that move, unless it's all about a kingside castle.

Is there a different general philosophy, BTW, with the king vs. queenside castle? Obviously, you've got an extra piece to move out' the way. Seems like that results in a significantly different dynamic with the pieces that are evacuated.

Impetuous as I am , I shall move now, and reflect later (with 97% efficiency ).

P - Q3