Could be so the time is better synchronised with the rest of Europe, which is relevant for business reasons. I seem to recall reading recently about some other country doing exactly that (though it wasn’t Norway).
Mexico used to have daylight savings even though they're close enough to the equator that it doesn't make sense - that's to harmonize with the US. When they did have daylight savings time, though, the state of Sonora didn't, because it borders Arizona, which doesn't.
