Anyway, I don't know about people using music-oriented software like Vocaloid. But I know that some people use regular TTS (text-to-speech) software when publishing videos. For example they may use the built-in MS Windows or Mac TTS function. I think it's not common in real-time streaming, though.
I think some people have done this for anonymity purposes. Maybe some do it because they are not confident in their language skills. I vaguely remember some people using TTS to replace character voice-acting. Others maybe do it for the aesthetics, that is, for lulz, I suppose.
