Why won't you ask your friend ?

But I will explain from my perspective since your friend could be slightly "different" (thats kind world) and could say dumb shit like "japanese language is superior".

I watched avengers with english voices - I could watch dubbing which would be easier to understand, but I decided not to. I watched tv show called "Dark" with german voices + subs, but i had a chance to watch it in english dub - still went with original. I watched chinese cartoon "Quanzhi Gaoshou" with chinese voices and if there ever will be jap dub then I won't even touch it. And I watch anime with jap voices - If there is only english dub avaiable then I don't watch it.

Why ? Try to draw your own conclusions.

Why should i watch it in a language i dont understand?

Only person living in Hamburgerland could say that. No offence Muricans in general, but yea - a lot of you have this kind of approach