She is not a model/actress in the show. She makes clothes. Would you wear fancy clothes at your workplace.
So if she is a fashion designer then she should always dress up. I don't know in which business line except for actor and model have you seen someone dress up fancy every time. Its not like she is walking under the spotlight on the ramp. And the fancier the clothes the more uncomfortable they are. And I think that one cannot work to one's potential if they are uncomfortable. And as mentioned in the drama that she is a workaholic and I think that she values her work more important than how she looks. On the other hand Hwang Chi Sook always dresses up as she doesn't gives a fuck to work.
is there a love triangle between Choi Woong, Gook Yeon Soo and Kim Ji Wong?
I feel that Kim Ji Wong likes Gook Yeon soo because when he was checking out the documentary from the past he was mainly looking at the parts which had both of them in it. Also when he met her he couldn't take his eyes off her. And he also went to check Woong's reaction when he told him that he met her. Hopefully I am wrong as I hate love triangles.But I don't think I am gonna be wrong. But I think it is gonna be a love square as NJ is getting interested in Choi woong too. Although it is not yet at a romantic level.
https://www2.dramacool.sk/snowdrop-2021-episode-1.html