In which situation should you deploy NetExpress at a large corporate enterprise?

You would never deploy NetExpress at a large corporate enterprise. NetExpress has insufficient capacity for any type of deployment.

To provide a solution for collecting packets, with no need for any other sort of analysis.

Multiple locations in widely disparate geographic locations with a need to monitor each location independently.

A need to provide visibility to a subset of an entire organization such as a specific group or collection of groups. without providing that same visibility to the entire organization.