Take note, Casinos will ask or demand a KYC if there's a big winning involved, is this one of their ways to scam their players?
It is a debatable question, no matter how hard to accept this fact it is still one way for casinos to verify user identity. I personally don't deposit as much as the amount that can be subject for KYC verification and it is not safe to share personal documents with third-parties. The same idea is true for some crypto exchanges as well. Maybe they use this method to scam big winners since it is rare to see complaints about the casinos which block user accounts that lost big.
That means we play it safe in gambling because depositing below the minimum KYC limit will not be asked to do KYC. Even though the casino can request this later at any time, we can still enjoy playing gambling anonymously so we don't have to send any documents.
But we also need to be prepared if the casino asks us to do KYC one day. I'm not very confident about submitting documents to any site for KYC purposes but if that's a requirement, I'd choose a site that can really be trusted.
And as long as I haven't been asked to do KYC, I haven't done it even though it's to get a bonus that requires KYC.