I think many people misunderstand what it means to be a good singer

A singer's job is to share the emotions contained within the lyrics and melody of a song with the listener.
That is why, even with the same song, there are times when one singer makes you cry, while another singer's version feels just mediocre.
Even if the pitch or rhythm differs from the original, the fundamental requirement of being a good singer is how well you understand the emotion of the song and can share it with others.