I can understand people preferring the money spent on hiring an additional developer to add features to the game. You could probably play the game without any sound at all! Page 24 of this PDF has the rates:
http://downloads.bbc.co.uk/contributors/bbc-equity-tv-agreement.pdfI think most game studios are not aware of how much value a professional actor can add to the game, if the talents are well involved. "Here you are mate, read this. Bye!" Ideally, the actors ought to be in communication with the team writing the dialogue at an early stage. If the Art team and the Sound team haven't learned from the actors and incorporated this into the game, it is a waste.
IMHO Larian generally do a pretty good job with this, at least starting with Divinity 2 (Divine Divinity and Beyond Divinity were their own thing in that regard...) I'm not sure how involved the VAs were then but the acting really fitted the game well and it's improved through DOS and DOS2 which seemed to have a lot of actor engagement, or at least it sounded like it. Contrasted with several games I've played where the acting really did sound pretty much like it was phoned in with no direction.
I would expect this to be at least the same standard as previous games and may even improve on them.
One thing I'm not so sure about is blowing a huge chunk of the budget on A-list actors: a number of studios have done that and tbh a lot of the time a jobbing actor better known for bit parts in the usual carousel of TV dramas and soaps can do as good a job and it avoids the pitfalls of a game character being eclipsed by their actor.
