Is project sponsor the same as benefit owner?

Often yes, but they are not quite the same. Think of project sponsor of a new,accounting system as finance director. The Benefit Owner is the person who is held accountable for the successful delivery of an identified benefit. For example, the new system might be expected to accelerate receipts from customers but it would be the credit controller who would be responsible for ensuring that the system delivered that benefit.

I see. Thanks for the explanation Sir Ken! Best regards, Kyle