Passion is a lie

Hey guys, I've been reading this book called, SO GOOD THEY CAN'T IGNORE YOU. It's basic premise is, that most of us don't have any intrinsic passion and it's fine. But most of us spend a lot time wondering what our true calling in life is, when there isn't any. So the author argues that, you should get good at something rare and valuable (He uses the phrase career capital). And use this career capital to frame a career that offers you control, has an impact and has a creative element to it. After reading this book, I'm starting to reconsider my PG choice, I was sure it will be a Medical branch and told everyone I would get into medicine. But now I have realized, it's not about the best you can get, but the best you can give. So I'm thinking, taking up dermat. What do you all think? Do you buy the passion idea too? Do you think passion should be a relevant tool in deciding the pg branch?

TLDR- Do you think passion is important to create a desirable career in medicine?

Thanks