The primary purpose of developing interview questions is to gather user feedback and insights. Effective interview questions are meticulously crafted to elicit detailed responses from participants regarding their needs, preferences, experiences, and pain points. This information is invaluable in the UX design process, as it helps designers understand user behavior and develop solutions that meet real user requirements. By focusing on users' thoughts and feelings, designers can create more user-centered products that enhance the overall experience.
The other options do not align with the goal of user interviews. Wasting participants' time is not a legitimate aim and runs counter to ethical research practices. Creating a project budget is more related to project management and resource allocation than to user insights. Analyzing market trends typically involves data analysis and research methods distinct from direct user interviews, which focus more on individual user experiences rather than broader market data. Thus, the focus on gathering user feedback and insights is crucial in ensuring the design aligns with user needs and expectations.