First, these devices will tested for UIDAI Proof of Concept (PoC) project, which will says whether it is technically feasible for India or not. If everything goes well, hope so, then it will taken in implementation.
Biometric capability also adds up in these two features of UIDAI:
1. Authenticating a Person: Through UID number and internet connection, one will be able to authenticate a person against the supplied UID.
2. Anywhere: Online presence of UID authentication can provide a platform to authenticate a person almost anywhere in India; what you need is just an internet connection.