There are certain limitations (which will get better in time) and it's also because it is a stylistic choice. Vocaloid certainly created it's stylistic niche due to early limitations and it is quite hard to find songs in other styles using voicebanks that are suitable for other styles.
Even if Vocaloid is capable of much more than just Miku, Miku is immensely influential in the subculture.
Does it sound better live ( https://www.youtube.com/watch?v=K_xTet06SUo )? Or for a closer comparison with the first link https://www.youtube.com/watch?v=nepNc0Gk1E8 ? Sure, even though the Vocaloid style has its own charm. But you also do not need to be able to be able to sing in order to create a song with Vocaloid, so overall it's a great tool. If the song is good, someone will eventually cover it live.
Vocaloid allows many who want to compose but do not sing to participate in a remixing ecosystem. The collaborative nature of the community is an incredible strength.
EDIT: That being said Miku can also be amazing: https://www.nicovideo.jp/watch/sm23655091
The original in a more Miku style: https://www.youtube.com/watch?v=PqJNc9KVIZE
Or a more jazzy version but not as good as the first: https://www.youtube.com/watch?v=CwG9viczjhs
Compare to a human cover: https://www.youtube.com/watch?v=fEsyBaG-uNw
Here is a different example:
https://www.youtube.com/watch?v=gIBdpzporFs
Of course the original version which is true to Vocaloid style is like this:
https://www.youtube.com/watch?v=Mqps4anhz0Q
Even if Vocaloid is capable of much more than just Miku, Miku is immensely influential in the subculture.
Does it sound better live ( https://www.youtube.com/watch?v=K_xTet06SUo )? Or for a closer comparison with the first link https://www.youtube.com/watch?v=nepNc0Gk1E8 ? Sure, even though the Vocaloid style has its own charm. But you also do not need to be able to be able to sing in order to create a song with Vocaloid, so overall it's a great tool. If the song is good, someone will eventually cover it live.
Vocaloid allows many who want to compose but do not sing to participate in a remixing ecosystem. The collaborative nature of the community is an incredible strength.