About to buy my first bitcoin and really confused about something.

So even though I know about Bitcoin since its inception the so called "lightbulb" moment just came to my mind a week ago. However, I have a mental block which is about valuation. If bitcoin is basically "digital gold" as it is not easy to transact with (thats what I read so feel free to correct me if Im wrong) the highest upside would be 11trillion (total gold market cap) divided by 550billion (current BTC market cap) and this is the best case scenario for it. What am I getting wrong here ?