That’s before getting into the jobs that are functionally not real, even if the employer in question believes they are honestly looking.

Seeing bog standard senior engineer positions still advertising for the places that ghosted me 5 months ago means the job posting is fake for one of the n-teen reasons companies paste fake postings or the company has gotten unreasonably picky with how much labor is on the market

To your point: You could make a fake company with a fake job posting in probably 15 minutes, and use it to easily waste hundreds of hours of time in people's lives.

Edit: Maybe it could be used to start some sort of unemployed software engineer fight club?