On the other side, you have one data store (the server-side) which is automatically backed up daily (by the normal server systems) and it maintains data integrity too. You know therefore, should the end-user delete their own 'front-end' interface; not all is lost - You simply give them another 'front-end' to use knowing the 'back-end' database was never at risk. Each user can change objects (if enabled) or more commonly, add their own queries and reports to provide local based processing which will not disturb the main hub of the database. Users have also been known to use the likes of Microsoft Excel to run 'one-off' types of reporting like Pivot Tables by connecting directly to the 'back-end' database.
In larger organisations where it's not unusual to have several departments with different versions of Microsoft Access (as far back as Access 97) that having a 'back-end' database on the server can be in essence an earlier engine Fax List format (i.e. Access 97 or Access 2000) where the 'front-end' objects can be based in either Access XP, 2003, 2007 or even 2010! Migration is kept to absolute minimum. There are other benefits to splitting an Access database but I think the above will be a good start. How you split an Access database is simple enough - you'll find this in the Database Utilities and Database Tools section (depending which version you are using).
In fact, locate the Database Splitter Wizard tool this will do all the hard work for you! Another tip for you! Before you split the Access database, it is always recommended that your first Back-up the database and then carry out a Compact and Repair Database action which are both available in the Utilities or Tools section (depending on which version you are using). A database in essence is what is considered a collection of information that is related in some manner. For example if you were running a company and selling a product you may have a database that simply lists all of the sales you have made over a period of time.