Martin Kuppinger clearly articulates the business value of versatile authentication (support for different authentication methods).
The business value is easy to describe: Reusing existing strong authentication technologies for more use cases makes things cheaper. Being able to use expensive very strong authentication where required but relying on other, cheaper, and appropriate technologies in other use cases reduces costs. Logistics for reused strong authentication technology is cheaper. All use cases, including external users like customers and suppliers, can be supported.
Overall, supporting versatile authentication is more and more a standard feature and the “versatility” of platforms for authentication is, from my point of view, an important point when selecting vendors. Hard-coding strong authentication into applications doesn’t really make sense anymore.