Delayed transfer of funds from Standard Bank to other banking accounts using the Banking apps.

In trying to transfer funds to beneficiaries using the banking app, Standard Bank holds the funds in a 'supension' account for considerable periods of time (whether funds are transferred immediately at a cost, or not). The funds are removed from the payees account immediately. Is this a way of Standard Bank making additional revenue? With Standard Bank to Standard Bank transfers there is no option to do "immediate" transfers, just a promise that the funds will be transferred within 12 hours. With other banks the bank transfers are virtually immediate in my experience. With Standard Bank, even with "immediate" payment to get the funds released requires a call to the bank to get the funds released in any reasonably short time.