Why is there a 24 hour delay on every transaction?

I made a new account the night before last and my brother tried to send me $150, but there was a 24 hour delay on the transaction. After calling customer service and dealing with the poor automated bot that "helps" customers before dealing with a real person, we were basically told that there was nothing they could do and I would just have to wait a day or two to get the money. My brother tried to use my mom's account (considering it's been active and was made years ago) to send the money to...

Why is there a 24 hour delay on every transaction?

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