This difference is a matter of perspective. We are talking about the same service catalog but seen from different points of view. The business service catalog (also known as ‘customer view’) is what end users see on their side when they access the service catalog to request a service.
You can imagine it as a storefront for users or customers to browse services, and from which they can request support. On the other hand, the technical view (sometimes known as the ‘supporting view’) is the internal view that contains information relevant only to the service provider and that outlines the workflows of a specific service in order to meet customer needs.