The current implementation of bank rules does not allow for overriding the description of the bank account transaction.
Currently, only the description of the "account’ (in this case, the expense account) can be defined. Values of the original bank transaction cannot be modified in the rule:
Ideally, this feature could allow overriding the fields description, or even the field reference, of a “cash or cash equivalent account” transaction.
You can modify the bank transaction description (or reference) later, manually, by clicking and modifying each bank transaction, but the process is cumbersome, time-consuming, and defeats the purpose of having “rules”.
That might be a way of working around these issues:
How to improve general ledger transaction presentation?
Import bank statement - “Reference” field no longer recognized
