I'm not saying that you need to pass KYC just for the sake of earning a couple of bucks on quizzes. But if you are planning or already trading on Coinbase - I think this is a pretty cool option, which ideally will give you a little knowledge about this or that project.
I appreciate your point, but there are a few caveats worth pointing out.
Firstly, if you are planning on using Coinbase and don't already have an account there, then you should absolutely change your mind and find a different exchange. They are easily the most immoral and anti-bitcoin exchange in existence, caring only about their profits at the complete expense of all their users.
Secondly, recognize these "learn and earn" activities for what they really are - ways for Coinbase to make profit. You complete the activity and earn a few bucks of a shitcoin. Great. You decide to buy a bit more of that shitcoin - Coinbase profits, and you lose out because the shitcoin loses value against bitcoin long term. You decide to withdraw that shitcoin - Coinbase now links your shitcoin wallet to your real identity and sells that to third parties.
So, if and only if you already have a fully KYCed Coinbase account and you plan to immediately sell the shitcoin you earn for bitcoin (and of course pay the trading and withdrawal fees), then completing these activities might not be a complete waste of time. For everyone else, they should steer clear.