When I install the accounting module, openerp creates sequences that seem not be used ...

Account Default Bank Journal Account Default Cash Journal Account Default Checks Journal Account Default Expenses Credit Notes Journal Account Default Expenses Journal Account Default Miscellaneous Journal Account Default Opening Entries Journal Account Default Sales Credit Note Journal Account Default Sales Journal .....

These sequences are defined in account_data.xml whereas Sales Journal, Sales Refund Journal, Purchase Journal, Purchase Refund Journal, ... are created from the account.py (create_sequence function).

Why the use of these sequences ?