Bank Entry is used for three main functions:
Batches of Bank transactions may be saved for later completion if required. This means that the batch may be entered including any unallocated payments, then saved and recalled when research has been completed to identify the missing information. The batch can then be committed which will update the loan balances.
The Bank Entry facility is also used to edit imported bank transactions. When you import a batch, some of the payments may be unallocated, which means that you need to identify the correct loan for the payment. In this case you may delay updating the loans when you import them. They will then be saved as a Bank batch and you can recall this batch through Bank Entry and enter the missing details before committing the batch.
The difference between Bank Entry batches and Transaction Entry is the "bank" aspect. Bank transactions make up a lodgement which, when transferred to the General Ledger will import as bank transactions and be available in the bank reconciliation.