Viewers when a girl who will never meet them or acknowledge their existence has a semblance of a life:
Any vtuber will tell you this is the type of person they want to avoid at all costs. Dude literally thinks he's doing Nina favors when she'd probably be weirded out like hell by his behavior.
Even streamers who do GFE content often times regret having fans like this because they're absolute freaks who will get crazy ideas in their head and start doing insane stuff outside of stream.
I know a vtuber who had a dude in chat who used to donate a LOT for attention. Just dropping massive wads of cash out of nowhere to get her attention, also changed his username to a very attention grabbing one. On stream this vtuber would try to act nice because obviously money is money, but she felt forced to change the kind of content she did, such as avoiding playing games this dude liked so he wouldn't come on the stream and beg to play with her (she let the audience participate in some games). She also started toning down her responses or not focusing too much on him, and the dude started openly complaining online (not in chat but in his social media) and saying he was sad he wasn't getting attention and wouldn't send more money as a result. It completely ruined her mood for a while because, up until then, she had always been super nice to her fans and interacted with them a lot online (we're talking a small time streamer here). She had to reshape how she dealt with donos and people like that in the future, it gave her a lot of stress because she felt she wasn't being as true to herself (she really wanted to interact with chat more but learned the hard way she couldn't do it the way she had so far). All this to say people like this dude are what ruin streaming for both streamers and fans.