This has number of advantages:
You get always full history on your customers, suppliers, employees and other accounts
You can generate multi-year comparative financial statements
All your business data are in single Manager file instead of being fragmented in separate files
End-of-period accounting adjustments can be made well after new financial year starts
Closing accounting periods
Manager is designed to be multi-year and doesn’t require you to close accounting periods. So when new financial year starts, you should continue using the same business file.