[ghostie_plz]

Both C#m and Db can be played on piano using only the black keys (skipping the 3rd note of the scale). This makes them easy keys for beginners. I'm not sure if that's the reason, but it could be related.

Anecdotally, I know a few vocalists that sound great in these keys and use them as a starting point

[thaumasiotes]

> Both C#m and Db can be played on piano using only the black keys (skipping the 3rd note of the scale)

For the major scale, there are 7 notes in the scale and only 5 black keys; you also need to skip ti, the 7th note.

For the minor scale ("C#m"), it's worse; only four of the five black keys are part of that scale.

And I would have thought that something intended to be played only on the black keys would be described as using a pentatonic scale anyway?

[thaumasiotes]

As a belated followup, I should observe that if you're playing "in C sharp minor" on the black keys, you're skipping notes 3, 6, and 7 of the scale... and those are the only notes that differ between a minor scale and a major scale, making the "minor" designation completely meaningless.