Specifically, on Norwegian 787s, you are briefed:
"In economy seats, reach for your mask. In premium seats, pull the streamer for the mask to drop the full distance."
Now the overheads in premium and economy appear identical:
And the premium seats are merely larger versions of economy, they're not beds or fully-reclinable. They're set 2 - 2 - 2 rather than 3 - 3 - 3. I'm guessing there are just two masks in each premium overhead where there would be three in economy, but that doesn't explain the "streamer" (which is just a piece of red cord).
So in premium there's an extra step; of course you end up with exactly the same mask. It puzzles me what the thinking is for the "streamer".