I think the best question is, what are you intending to use the transactions for? You don't have to use a status like "Returned" if you don't want to or your payment processor does not support a similar status.
Different payment gateways provide different transaction statuses, and the statuses Blesta supports covers pretty much all of them in a generic way.
Typically:
Approved - payment received
Declined - payment declined/refused
Voided - payment voided/invalid
Error - payment error occurred
Pending - payment may be received but awaiting confirmation; on it's way; authorized but not yet captured
Refunded - payment was probably Approved in the past, but has now been refunded back to the client
Returned - payment was probably not Approved in the past, but any money received was returned back to the client
Use, or don't use, those statuses to your liking, but "Approved" should be your successful payment received status and all of the others are not.