Makes sense, I guess. It's understandable that they'd want extra money for it normally. In many cases, voice acting costs are based on the expected size of your audience, so having japanese voices available for everyone in the entire world could mean they'd have to pay a lot more for the voice acting, even though only a minority of the EU and US customers would actually try it, much less base their purchase on its inclusion. However, making it a separate and optional feature solves that issue. I hope this is something other developers and publishers would consider as well.