That is part of a service that we use, provided for some banks, but requires a lot of integration with the mobile networks and a lot of additional business logic around new sims, old sims used on new accounts, old sims used on old accounts when first set up, etc. Banks use it for determining whether it is deemed safe to send OTP or other sensitive messages to a mobile. If sim has been swapped recently, they may then choose not to use text message delivery to prevent potential sim-swap fraud.