Adding new item to UITableView


I am wondering why in the - (IBAction)addNewItem:(id)sender method, authors decided to go with adding elements both to BNRItemStore and tableView solution.
I think, that it would be neater and less error-prone to:
[li]update BNRItemStore with inserting new element[/li]
[li]call - (void)reloadData method of UITableView.[/li][/ul]
Are there any particular drawbacks of using reloadData?