Its one of those things in the variation of human perception and imagination. Since I've got middlin' severe aphantasia its always an interesting topic to me.
Sight-reading music can be an important skill.I have read, or maybe heard, that there are people can read a score and hear the music in their head, a combination of absolute pitch and musical education, I have to believe. This is not me: I was never any good at sigh-reading, and my sense of pitch is ... kinda approximate.