Why different? I have no idea. About "Dutch" that is derived from "Deutch", I think. Or possible the other way around. Never came across that piece of information in any history book I've read, not that I remember anyway, just a qualified guess.
If you're interested I have a couple of links to Dutch coin pages. Can't read them very well myself but I've still found them useful on occasion.
Best of luck with your holiday plans
Lots of different possibilities there. Iceland, with just over 300 000 inhabitants, is more than twice the size of the Netherlands...strange to think about, really. And Norway three times as large again.