Senjutsu debuted at #21 in New Zealand, sits at #9 this week they finally woke up
Yeah, correct. Nightwish landed at no.5 on physical sales charts and did fairly better than debut of Smith/Kotzen in US. Anyhow, my point is that Nightwish is not a very popular band even by Metal/Hard Rock standards. Their best certification is just one Platinum in Germany. Not even a single Gold/Silver album in UK, Italy or France, let alone the other parts of the world in a career spanning 25 years. I know they are very big in their homeland Finland, Germany and some parts of Europe, but that's it, they don't have much impact & influence elsewhere.