The main advantage of using an ODBC connection is that it provides a layer of indirection between the application and the database to which it connects that can be remotely administered.

This is most useful in large organisations where the data the application uses may be split amongst various physical DB servers along political, departmental or physical location lines. The application can be deployed to workstations without change and which actual server it connects to can be control through the administration of the local ODBC connection. Often remotely.

It also provides for a level of isolation between the application and the type (vendor) of the DB holding its data. The caveat woth this usage is that the application must restrict itself to a common (non-proprietary) subset of the DBs SQL.

So, if you think the application might need to switch from using a local DB to a remote one; or from Oracle to DB2 or MySQL or Access at some point in its lifetime, then using ODBC up front might save you some hassles later. But as with any level of genericity, you must be aware of the restrictions it imposes, and unless you have a fairly strong belief you are going to need it, it is probably best avoided.