What I have in my mind, this module may work for products that are used as raw materials in manufacturing for example, you don't sell purchased raw materials, yet you need a module to notify you if you're low in raw materials, I think this module with modification will serve that purpose

As I understood from the module, if I put a negative number in field "notify on qty" then the product would be ignored by the module, if I'm correct then you can change the module to work with all products not just saleable ones, if I wanted only sealable ones then I would update "notify on qty" to be negative on all products except sealable ones, this way we won't change your module's current purpose but we're extending it ? if I'm correct so far,then maybe move the field "notify on qty" to group "inventory", I think that field is more appropriate to be there

What do you think?