Like with everything in the world, the problem is how humans will abuse it. See the sheer amount of AI slop people create to flood the zone
>>98365255 or overtly evil means to control information like like pic related.
As for Vtubers themselves, they want to cultivate a community of original work and people, not mass produced AI images that all look the same. Heck, just look at the OPs for the fan generals on /vt/, Hololive threads generally disavow AI, meanwhile other threads like Phase Connect spam them. You can draw your own conclusions from that.