Sleepy-girl representation is important
Wow! I've never been able to get into audiobooks, but is it a normal practice for dubbed characters to have their original anime VAs return? If so that's super cool and I might have to look more into this.
Light novels tend to switch point of view characters a lot, so audiobooks then tend to get a male and female narrator voice and divide sections up between them based on point of view character gender - so for series with popular dubbed anime (like say, Sword Art Online) they quite often get in the two lead voice actors from the dubs to do that with. It's a very common workflow.
I'm not really an anime dub nerd, I'm more of a subs dweeb so i usually have no attachment to these voices - but i have watched the Slayers dub... because come on. its Slayers! SLAYERS! If your a Slayers enjoyer OHHH BOY do i have a treat for you. Just listen to that audiobook version! NOW THAT'S SLAYERS. THAT IS LINA INVERSE READING HER OWN DANG STORY. Shes DEFFO just bragging to you about how cool she is. 10/10 would recommend.
(NOTE this clip is from Slayers Vol. 1 and is the sample published on Audible. Go get the book there! Or somewhere else if your not locked in to the amazon platform! Its good!)