Ultimately it is nothing but an upfront investment I have to make just to gain an interview, without a guarantee for a job. How would you like a job ad that read "to apply, send us 1000$ in cash"?
The advantage of places with puzzles is that everyone else had to go through them too (you hope; if it's just you, something's wrong). That keeps the bar high and ensures you won't be working with idiots.
Most worthwhile things require some up-front investment without a guaranteed payoff. Finance means putting the money up now for a hopefully higher return later. Education requires that you study now for skills later. Startups require that you build something now and hope you can get people to pay for it later. (Well, not always, but the bootstrap approach of finding a customer first requires that the customer pay up first and then take on the risk that you can't deliver.)
The trick is on doing due-diligence on the job first and making sure it's something worth investing in.
I don't know, maybe rather than wasting time on random puzzles, it would be a better investment of time to create some cool application as a demo? I don't think any startup would require dhh or pg to solve some puzzles before considering their job applications.
With college also, you get something in return for your investment (hopefully) - skills.
Of course if you just feel like chilling, why not choose some job puzzles.
You're welcome to write a few books and become well-known for your business or programming acumen as part of your investment of time early on for future payoff.
Ultimately it is nothing but an upfront investment I have to make just to gain an interview, without a guarantee for a job. How would you like a job ad that read "to apply, send us 1000$ in cash"?