You know, I'm not sure.
In this case, the cheque would be cut by the crown to the offender. The offender doesn't have access to the bank the way you and I would, or frankly, even the way an offender might if he were on conditional release in the community. An in-custody offender would have a different circumstance from an offender serving a similar sentence for a similar crime, but only he had now been released on day parole or full parole.
In any case, if the offender is in custody, they have very different access to their account, and CSC controls that. If it weren't CSC being administratively involved, it begs the question, who would be? The court can't reach into that offender's account. The creditor obviously can't, or they would already have done so if there were a mechanism for them to do that. The cheque gets deposited on the offender's behalf, but administratively, CSC is looking after that offender's bank account.
It's not like you and me just going to a chartered bank or to an ATM.