Online course creation without brand - pros & cons?

Hey everyone! What do you think about creating online courses as a side project or a side hustle?

There's a lot of advice nowadays pointing people to create online courses to help build their personal brand, make passive income and develop an audience. Some people like Ali Abdaal have said (in the IndieHackers podcast in fact) that all you need is more expertise and experience that someone 3 years younger than you to teach something, and that everyone has a course inside them.

Then there's the counter-arguments around needing a brand/audience first, being truly qualified, being able to market it well, etc.

What do you think?

• Do people need to be an expert prior to a course, or do people become an 'expert' because of a course?
• Can you truly make money off of online courses quickly?
• Is it really one of the best ways to build an audience?

Just thinking through these questions myself recently and wanted to share and see what everyone thinks :)