Final answer:
The drawback of digital sales channels is the limited personal interaction which can impact customer service and the ability to build strong customer relationships. The convenience of digital channels comes at the cost of traditional customer engagement that businesses usually experience with physical storefronts.
Step-by-step explanation:
Among the options provided, C) Limited personal interaction is a drawback of digital sales channels. While increased reach to customers, higher cost efficiency, and faster transaction processing are all benefits, the reduction of personal interaction with customers can impact customer service and relationship-building efforts. Without the face-to-face engagement found in traditional sales environments, it becomes more challenging for businesses to build rapport and understand the nuanced needs of their customers.
Considering the e-books example, digital sales channels allow readers to access and purchase books with convenience and often at a lower cost. However, this can lead to the detriment of brick-and-mortar bookstores and publishers, as the traditional personal interaction and the physical browsing experience they provide are diminished. Authors selling directly through platforms like Amazon could further bypass publisher relationships, undermining the traditional distribution channels and their associated personal interactions.