Ironically I heard this from a streamer but streamers are like the fast food of social interactions. Humans are inherently social creatures , we get very sad if our need for socialization isn't met , watching a streamer can give you a similar feeling to talking with friends.
Is it as good? of course not but maybe its good enough if you are tired from work and have time to spare. This of course can be dangerous when people get too attached and streamers who lean in to the whole parasocial aspect. Why go through the effort of and hardships of maintaining and building relationships when you can get something that scratches that itch in your brain for no effort.
Everything in moderation. McDonalds for every meal is of course bad but its fine if its part of an otherwise normal diet. But if someone is starving to death McDonald's is a whole lot better than nothing. I view streamers the same way.