Computer generated voice has certain artifacts that makes it a bit distinctive. Auto-tuned natural voice has similar artifacts, so if an artist uses auto-tune, then there's less noticeable difference between their real (computer-altered) voice and a fake computer-generated voice.

A more exaggerated example would be artists that use a vocoder (e.g. Daft Punk or something like that), which would be even easier to synthesise convincingly because the real vocals are also mostly synthesised.

Less "uncanny valley" affect, because in both cases, you're hearing a synthesized voice.