In general, retail stores (that are not owned by large corporations) do not have the vast financial resources that can be commanded by multinational organizations. They’re not able to invest thousands of dollars into purchasing equipment that quickly depreciates. On the other hand, they also do not have the expertise required to maintain their own phone systems. Businesses can very easily get started with VoIP and they do not find cost to be a significant obstacle.
If the organization already has analog phones, they can use it with the VoIP service simply by connecting them to ATA adapters. Employees can even use their existing mobile devices for making or receiving business calls by downloading and installing mobile VoIP applications that are compatible with the service.