90% of the time the acting will be better in Japanese. That's not because there aren't good actors in English, but because the pool of people that audition for jrpg (because lbr the only games weebs like me care about having Japanese voice acting is jrpgs) voice acting in English is very small. So you end up with two choices: hear that same voice you've heard 5000 times or hear someone really mediocre or downright shitty. It's better now that it was ~back in the day~, but it's still really noticeable.

Also, with games like this the great majority of the players will be playing almost solely for the characters and story. Having subpar voice acting really lessens the experience, so it absolutely is a big enough deal to just opt out of a game entirely.