You can be the best at what you do and still lose to someone half as good.
Being good does not make you visible.
Nobody can choose you if they never saw you.
You can build in private, but the deciding happens in public; most people pour everything into the first and nothing into the second.
A personal brand is about building in public - not private stuff made public: your ideas, your thinking, your take - out where people can find it.
Would you rather hear from the founder or sit through another contrived advert?
Exactly.
There's one of you. You are the advantage - but only if people can see you.