Obviously it would be more work for an agent to issue a refund after a certain amount of time has passed, but I would imagine it still can be done as situations arise. For example, wouldn't CO refund my ticket if they canceled service to an airport I'm booked to fly to/from?

The only way I would take the voucher is if I knew for sure I would spend it soon AND that it would work the same as cash (like a bump voucher, no restrictions, no EQM issues).