Does provide you a product availabilty tab in your sale order view. You will be able to see availibilty for each product in the sale order in each of your warehouses.
Does allow you to create a special URL with an access tokken, where your phonebook can get access read only from remote. This is useful for example to get your contacts into the phonebook of your local desk phone. This is the basic module, you do need also a model specific module depending on the desk phone you are using.
Does add export format for yealink Phones
Does allow you to go beyond the 2 levels of website menüs