My fave scene! Nam Dosan is actually doing a method used by UX/UI designer to empathize with the user of their product. NoonGil is aimed at people with visual impairment, thus understanding their experience is a crucial aspect for generating an inclusive design.
User feedback is an important aspect when developing a design. It is crucial for analyzing users' experience while using the product, and how this information can be applied to build a more effective design. Dalmi & Dosan is exemplary as an inclusive designer!
As per ep.9 I believe Noongil is still a prototype(later Dosan upgraded it based on the feedback). So idg why their mentor reacted negatively to how Dalmi engaged with the comments. He did make a point abt reacting based on data but in the end, what matters for him is the profit