I am able to replicate steps and arrive to the option price using Black Scholes framework. Here however I am more interested to understand, at least intuitively, why the ln transformation of price process is performed (Ito lemma part) in the first place. Price process is already a function of time and Wiener process, so I wonder why do we need to apply another function (ln). I do not think it has to do with log normality of prices or normality of returns. I have seen such a transformation taking place in solution of other problems that were not related to GBM - BS framework.