The truth is that, today, if I was going to use a tool to generate voices (say for YouTube), I wouldn't necessarily pick a small SaaS tool. I'd use Amazon Polly or some other GCP-style platform voice creation tool. There are already a few products in the space, and their costs are so low as to be almost negligible (example: Polly, 5 million characters free). For a commercial project, I could probably stay on a free tier for a whole year.

With Dall*E, it seems like the only option, and it's such a superior option that a website could abuse it for commercial profits. But for voice synthesis, it's already dirt cheap and commercially available without limitations.