In the first case the customer is really looking for a large shared hosting plan that allows multiple domains. More frequently in the industry you see the term “Multi-Domain account” to refer to these plans. These customers can be webmasters with a network of websites, web designers, or a company that wants separate websites for their different brands.
These accounts can also be less inexpensive then traditional Reseller plans because they do not need to offer all of the services such as Private label branding. They are essentially shared hosting accounts that allow for several domains.
The second customer is really looking for a turnkey business, a franchise of the parent hosting company if you will. These customers are hosting companies who do not want to carry the overhead of a datacenter or series of managed servers. Using a Reseller Hosting plan allows a hosting company to have a complete professional hosting company without all of the traditional startup costs. Like anything, there are trade-offs versus a dedicated server, but for a small hosting company or startup it is an ideal solution. It allows them to focus on growing a customer base and not infrastructure issues.