I agree with your someone. Lots of anime characters have extreme accents to help people identify their personalities more quickly. Just like you have "classic" accents in China (the old man, the tough guy, the cute girl, etc.), classic Japanese accents are commonly used in anime. If you speak exactly like that, people will think it's funny at first. If you keep doing, you'll start to annoy people. Imagine if someone spoke to you like a character in movie. Unless they did it just a bit as a joke, it'd get old fast. I think you can still use the material to study though. You can copy their basic pronunciation without copying the over-the-top intonation and you should be good. Just speak with your own natural intonation. Anytime you shadow Japanese, whether you ever actually intend to talk exactly like that or not, you'll be getting your vocal system more mechanically tuned to be able to speak Japanese fluently. I shadow female characters all the time. I just don't actually speak like they do when I'm not shadowing.