Depends what you’re looking for in a card.
Japanese has plenty of things going for it.
Japanese cards are the “true” first edition of the card.
Japanese cards generally have better card quality, and card stock. My old back Japanese holos definitely look and feel better compared to my wotc.
On a personal level I feel they look better with slimmer gold and then silver colored borders instead of the bright and fat yellow borders on the English. Many Japanese cards are rarer than their English counterparts.
The Japanese sets themselves are often better as a whole.
Honestly, just from a pure card quality and collecting perspective I don’t see how anyone couldn’t view Japanese cards as superior.
English cards, however, are English.
There are roughly 150 million people that speak Japanese, and several billion that speak English. The demand will always be higher just for that reason.
In the long run I think English will always be king, but Japanese will hold it’s own as the original. Other minor languages like German or Korean, however, have a much bigger risk of fizzling out, in my opinion.