Android contains an internal JDBC driver (SQLite.JDBC2y.JDBCConnection?). SQLDroid provides a number of advantages over this internal driver

• SQLDroid uses only supported, official APIs
  Use of the internal Android JDBC driver is not supported or recommended by the Android team. SQLDroid is built on the published SQLite API in Android.

• SQLDroid supports concurrent access
  The internal JDBC driver in Android bypasses the locking mechanisms present in the android.database.sqlite packages. This makes its use questionable in multi-threaded applications. By using only the android.database.sqlite SQLDroid also supports locking.

• SQLDroid supports BLOB
  Actually, it's probably the only SQLite JDBC Driver that does.

A longer discussion on the internal driver vs SqlDroid can be found here.