Just to expand on this.
A user on the Norwegian Insideflyer forum reached out to SAS and sent them screenshots of SAS staff saying you could only use your own points and asked them for confirmation.
He finally received a reply from Olivia, Head of Eurobonus, which cleared up that the previous information was not correct, and it's indeed OK to book with someone else's points:



Took the liberty of re-uploading the screenshot from that forum here, so you don't all have to sign up for an Insideflyer account.

I guess this is her: https://www.linkedin.com/in/olivia-wasniewski-1ba15826/
I'm only quoting from that forum - that's all I know about this. So please don't hold me responsible if there are problems. But it looks legit to me.