Me. Shiina shares more details about her personal life than any other vtuber I've watched, including ones who openly facepost. I think she's just lonely and parasocial, wants to share about her life like you would with friends. Doubt she'd be comfortable with a fansly.
Edit: Lol, live just now "I feel like this is the only place I'm comfortable talking to people is on stream"
Edit 2: Including socializing with coworkers. Quote from just now again "After every collab, I crash out. I cry. After most every collab I go to my room and cry about it"