Most banks use customer segmentation models, whereas design personas are better suited to web design.  They align stakeholders behind a shared understanding of the customer.  I’d argue they also support product design too.

Forrester Research: How Design Personas Differ From Typical Customer Segmentation Models

Traditional customer segmentation models don’t provide the key information about users’ goals, attitudes and behaviors that is required for effective interaction design — personas do. Valid personas are derived from primary user research, foster a shared point of view among the diverse group of people who impact the customer experience, and enable design decisions.

To make the most of investments in personas, firms should ensure that personas are valid, useful, and incorporated into a consistent design process.