Here's a real-world example from a client who uses Qualtrics heavily. At regular intervals following vehicle purchase, an automotive manufacturer sends surveys to vehicle owners asking about their perception of the quality of the vehicle, issues that may have come up, features that were not explained properly or don't work as expected, etc. We're talking hundreds of thousands of surveys a year, each with 20+ branching questions. The surveys themselves are built in Qualtrics (something that it is quite good at), managed by Qualtrics (yes, survey management is a big deal), and the top-level data analysis of the survey results is done in Qualtrics as well to determine if there are problematic trends that need to be addressed, more issues than in previous years, segments of customers who are for some reason perceiving quality differently than others, opportunities to redesign or better market things in the future, etc. This data is directly used to update products, training, marketing, etc. at the company.

This is, in my opinion, the biggest use case for Qualtrics - customer experience research based on surveys or data gathering methods managed from within the platform. You can think of it as Survey Monkey on steroids with some SPSS-lite data analysis functionality built in.