Free. I bite, What's the catch ? I presume recruit users to use the Wallet app ?
1. The "float". The interest that they make from the period that people have cash in their accounts. If an ACH takes 4 days to complete, they may take 5 days to complete it, and collect a day's worth of interest
2. The halo effect. Now you're a Paypal/venmo/square user, and therefore more accessible to vendors using them as a payment processor. Those vendors pay the service transaction fees.