It would be a huge time saver. Typically a pro does around 100 lines per hour, an amateur doing multiple takes would be significantly slower. So a character with 1000 lines could easily be 20-30 hours of work, just for a first draft. It would be pretty amazing to be able to just revise the script and auto-generate a new recording, even if the quality is only 90% there.

Just like with image generation models, this will massively raise the bar for what amateurs can do with a limited budget and limited time. It's hard to justify spending thousands of dollars on voice acting and art for a hobby project, but now amateurs can get something that is 90% there and substitute professional work if the project takes off.