Imagine winning and you find it hard to pass KYC, trapping your money on the casino for like ever.
It's not always the casinos fault, I know some are dubious but the thing is KYC verification is something you should first deal with before making your first deposit.
Online casinos can be frustrating at times, some casino won't accept your submitted document even when you haven't make any deposit on the platform yet, so always confirm your identity first.
Submit your identity and wait for approval, do not be in haste to make deposit first, because the identity you submitted without a green approval from the team can still be rejected, take your time to get the passed approval first before proceeding with gambling.