Cryptocurrency exchanges typically need name, address, passport, photo ID, etc. to ensure you are who you claim to be, which aids in the prevention of fraud and money laundering.
I think the teams are doing all those things to make sure cryptocurrency exchange users are safe in any transaction they want to carry out from the exchange market, without a username, it will be difficult for people to identify who they are transacting with in the exchange market which is very important for the cryptocurrency exchange teams to demand for your name, your address, passport, photo and ID, the prevention is that, it will be difficult for scammers to use your identity to scam other users in the exchange, it will make the coins you want to exchange to enter your wallet easily, it will make other traders or investors to know that you are the one using the cryptocurrency exchange.