It does not change the basic principles of its decentralization, but it will make new people a bit too confident in what legacy financial institutions offer as service. They will buy their coins through their bank, store their coins there, borrow, etc. It's very convenient, but also very sad to see happen because that goes against what Bitcoin stands for.

A lot of the people entering crypto do not even have their own wallet. All they know is buy/sell and send coins from one exchange to another and that's it. What has this to do with Bitcoin's decentralization? It will get much worse when actual banks are entering the space and outcompete the current crypto exchanges. It's done quite easily, especially if the bank closes the bank accounts of exchanges. Without bank accounts you can't onboard users.