//using inheritance
class Item //base item class
{
    string name;
    string description;
}

class UsableItem : Item //class that inherits from item and adds functionality to be Used
{
    public void UseItem()
    {
        //code for using the item
    }
}

//not using inheritance (flat)
class Item
{
    string name;
    string description;
    bool usable;

    public void UseItem()
    {
        //code for using the item
    }
    //simpler because it's all contained inside one class
}