I don't agree with that advice.

Interviewing sucks. I know, if you currently have a job then you don't lose anything. Other than precious time and I already feel like I don't have enough free time, I don't want to invest the remaining interviewing.

I have been in a few companies and yes, sometimes getting a promotion is literally impossible. I remember one company that didn't give me a promotion until I threatened to leave.

But if you find the right company, then you shouldn't even need to ask for a promotion.

And lastly, I would hope you are working for a company that you care about. That makes it more complicated to find a replacement