japanese steel

Ive scoured the internet but i cannot find any information… what is the purpose of Ion plating on a kitchen knife? The knife in question is the seisuke SK-85 ion plated nakiri japanese knife (175mm with white wood handle) referenced via picture. Is it just for looks? Is this brand reputable?

so everytime i search for "differences between japanese steels" its just an article that talks about how each steel has a different amount of tungsten than the other, or another chemical difference. It does not say "this steel is hardest to sharpen" or "this steel can hold its edge the longest"...