[hatsunearu]

The near-universal understanding in the fandom is that Vocaloid is a not a replacement for human voice, nor is it really aiming to be some sort of faithful emulation of it; rather it is "its own thing", like how a Piano isn't an emulation of human voice, nor is a DAW a replacement for a guitar or whatever.

[Open-Sourcery]

But for those that wanted an artificial singer, as far as I know there weren't really any more realistic sounding alternatives. It's nice now that instead of spending so much effort tuning vocaloids to sound realistic there is an alternative.

And knowing the limitations of vocaloid never stopped anyone from trying. Mitchie M is a great example.