99.9% of Western vtubers do exactly what streamers do, including being charismatic and entertaining, just behind a computer generated avatar. The "lore" and design of their avatar is mostly just aesthetics, a bit of branding and a means of self expression. Japanese vtubers take the kayfabe more seriously but that's because their personas are essentially corporate generated identities and that's their job - but even then their actual personalities inevitably leak out, and their talents become a part of the character.