I assume this is done by the company, not the IRS.
This allows tax prep companies to give people 'instant refunds' (essentially loans for the expected refund amount) so people don't have to wait weeks for the IRS to send them a check in the mail.
The IRS only pays out via check or direct deposit but the company who did your taxes can pay out in cash, gold, or pokemon cards if they want to.
So much fun :)