Dynamics Nav Logic Programming


I want to ask a simple question about the Nav logic programming .

In CodeUnit (23) : Item Jnl.-Post Batch ,The standard use a record variable to copy rec and after the code processing ,it assign ItelJnlLine to Rec.

My questions are :

Why the system use this logic ?Why don't use directly Rec?

What the difference between a simple assign and ToRecord.Copy(FromRecord)?

Thank you.