But I think "en möbel" would be a single piece of furniture like a chair or a table. Whereas "möbler" (pl.) would be "furniture" (sg.) or "furnishings" as a whole.
It's so annoying when I lose a heart because I wrote The instead of They! And that often happens... D:
As far as I know, duo is a bit harsh on typos that change the meaning. I've done the same and similar mistakes countless times...
What's more interesting is that in Russian, furniture is ''мебель'' (myebyel'). It sounds a lot like möbel, except it's used only in plural :P
More interesting still, we use "mueble" in spanish and it sounds pretty close to the swedish counterpart. And we also have a singular form. ;)
Even more interesting, in polish, one piece of furniture = mebel and furniture in general (plural) = meble ;)
It's not wrong - the word was borrowed into Swedish from French. I mean, of course you're right as well, but it has multiple origins depending on how far back you want to go. :)
It is a correct translation and should probably be accepted, though in my opinion "need" is a better translation since it sounds less formal.