[hashkb]

I wonder if these challenges are good enough to measure candidates experience

Doubtful. I think the code challenge is critical, but obviously not the only thing to consider when evaluating candidates. If you're making your decision based solely on coding challenges, you're gonna have a bad time.

IMO the right thing to do is to use your screening challenge to "set the bar" and eliminate people who (in the opinion of your organization) are unable to code their way out of wet paper bags. The bag thickness will be different for everyone, of course. Once the candidate has escaped the bag, so to speak, then you can (and should) evaluate more holistically.