Are Non-Inventory Items Vestigal?

Our decision to stock, special order, or drop-ship items is very fluid.  As the business grows, we often decide to stock items that we previously did not.  Almost everything we sell has the potential to make this transition.  Also, special order items are sometimes returned but not sent back to the vendor, requiring us to track them as inventory.  We keep our inventory light, so stocked products are often special-ordered or drop-shipped anyway.  As a result, the distinction between Inventory and Non-Inventory items really isn't appropriate, as NetSuite has implemented it.

A detailed comparison of the Web Services interfaces leads me to believe that at this point, at least in terms of the fields supported, the one is a superset of the other.  It seems there are some differences in accounting between the two, but I'm not an accountant, so I'm ill-equipped to judge their significance.