The part that's less cool: the pack costs $30, on top of the full-price purchase of the game. The massive upcharge brings the US Steam version into price parity with the Japanese retail release, which shares an April 25 release date with the VO pack, and retails for ¥7,980 ($80). Yes, video games are always too expensive in Japan. And Square Enix is artificially ensuring that's the case for Tomb Raider.
It's hard to figure out who this Japanese Language Pack is for, if it comes out the same day as the localized PC release for the same effective price. We suppose it's for people in Japan who want to play Tomb Raider now, but don't mind missing out on all the dialogue for a couple of weeks.