Banks do not purchase $XRP

If a bank wishes to utilize XRP,
it can do so by entering into a contract with Ripple
to access the ODL (On-Demand Liquidity) service
therefore, there is no need for the bank to purchase XRP itself.

However, in the future,
once Ripple obtains a commercial banking license,
banks will be able to hold XRP
and utilize the ODL service independently,
without needing to rely on an external provider.