This is a much better take.

Intonation is huge, and something general models tend to have trouble with - especially with something like an audiobook, which is narration - it's very contextual in a way not found in almost any other form of communication. It even encapsulates every other form of context through dialogue.

And not only that - a lot of audiobooks have versions by multiple voice actors. And they might change a word here or there, but it's highly structured data - it's truly a treasure trove

I'd go a step further and say they really want access to the dataset - not just for audiobooks, but because this is a fantastic dataset to train very context aware (and silky smooth) text to voice.

Spotify probably doesn't have the chops to do this, but they might be trying to leverage the dataset - I'm not sure if they could sell it wholesale or not, but if nothing else they could "partner" with Microsoft or Google to train VTT capabilities into multi-modal LLMs (a pitch with all the buzzwords to make investors need to change their underwear)