I normally do not like them.
They are stressful, unpredictable and sometimes plain silly (like playing with words).
But they offer a good insight in the company itself.
Let's imagine a company requires you to do a small assignment.
The level of difficulty is a 9/10, the code has no real life value, and the tech asked you to use is outdated.
This would help you a lot raise some green, or red flags about the company.
Also, even tho I don't like to admit it you will encounter coding puzzles a lot during development, so studying them early will help you in the long run. Last but not least if the company is a really good one and this was their only drawback I would sacrifice my time, once, just to be part of that company.
The problem resides when the job application is for a senior position.
If I would be in a recruitment process for a senior position with a lot of experience behind my back and they ask me coding puzzles compared to advanced, high level overview of things I would immediately stop the process.
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