My experiences with unions have generally been pretty positive. It's also important to recognize when unions are useful, and when they're not.
1) For workers in large corporations, since it can negotiate pay on behalf of the workers, and the company would otherwise have much more power than individual workers, and could otherwise easily replace them. Larger companies can also withstand the cost impositions a union would impose upon them directly and indirectly.
2) Highly-skilled workers, since the workers can't easily be replaced to sidestep the union and gives the union greater bargaining power in getting more benefits for their workers
3) Dangerous industries, like mining, forestry, etc, so unions can advocate for worker safety
I don't think unions would work for vtubers. Companies that see vtubers as not being replacable treat their workers pretty well (Hololive, Phase). Companies that see vtubers as replacable (Nijisanji) are just going to ignore the unions and replace the workers that want to unionize. The really small vtuber companies will not be able to survive the demands of a union.
Subverting labor unions such that laborers now associate them with retarded communist assholes is the single most successful anti-Conservative propaganda effort ever undertaken
The unfortunate thing about power is that it attracts the people that want to abuse that power, and that includes retarded communist assholes. The only people that subverted labour unions were the members of labour unions themselves.