My opinion: After the documents are sent, they go through a number of people and online casinos keep changing their staff from time to time and in some case, if a staff member knows my address and in case I am a high-roller I would be in some serious trouble because the staff member can track me and even blackmail me to some extent. I am ok with giving my identity to known sites like bet365 or williamhill but I am still not comfortable verifying myself at a lesser-known crypto casino.
Blackmail you for playing in Cryptocurrency casinos? I don't think so, there are many crypto gambling casinos than on fiat, you can even charge those who are blackmailing you because they have a contract about the privacy policy on gambling casinos they are working with and, you are right that if you want your money and privacy safe, play on proven gambling sites that knows how to protect your money and data.