Alternate interpretation: I always thought Lin meant to be a comforting presence.
Sheās the first bathhouse worker who is kind to Chihiro, helping her get her clothes and navigate her first work assignment and sneak food. One of the core themes of Spirited AwayĀ is finding your footing in a new and terrifying place, and Lin and Haku are key allies in Chihiroās struggle to gain the skills and self-assurance she needs in order to thrive.
Linās human appearance helps us and Chihiro feel more sympathetic towards her . Her familiarity with the system of favors and bribes makes her appealing as a role model who can demystify Chihiroās new environment for her. Unlike the more inhuman occupants of the bathhouse, Lin looks like someone Chihiro could become in the future, and thatās a good thing! Sheās living proof that the bathhouse is not such a monstrous and scary place. Because Lin treats the bathhouse like home, Chihiro begins to see it as a home, too.
And once Chihiro starts to think of the bathhouse as her territory, sheĀ realizes that she has agency in this place as well. She uses its rules to her own advantage to free Haku and herself.
And that is the point of Chihiroās journey in Spirited Away: itās a metaphor for starting over in a new place and overcoming fear of the unfamiliar. After all, the frame story is Chihiroās family moving to a new city. At the beginning of the movie, Chihiro is despondent, unhappy to be leaving her old friends behind. By the end, after making it through the spirit world, sheās taking a much more active role in helping her parents settle into their new home.
TLDR: Lin is there to be Chihiroās friend.
