No. Bitcoin banks are nothing more than a service such as Coinbase that is offering people an online wallet platform. I don't see why people don't seem to understand that. It's just a service which you can choose to use or not. It won't have any negative impacts on Bitcoin at all. You must know how many people there are that don't care a single bit about decentralization. They probably don't even know what it really means.
If they are offering people an online wallet platform then it is acceptable but i don't think so there is any need of these platforms as already we have variety of wallets which are more convenient.