Something as simple as a list built into the online account can make life much easier. The amount in his account will never be altered in any way but the data will be manageable and be used in different ways.
The bank can however use this personal data(with the consent of the user) to offer him different schemes. For e.g. A user spends Rs. 6500 on car EMI, this data can be used for different offers on financing a new/old car, replacing it with new ones etc. Same is the case with investment details.

There are a loads of services that can be offered to a user based on his account information.