My guess is that the shell on the jacket you bought is cotton. (The one time I’ve been into a Duluth Trading store, they appear to have a distinct aversion to nylon, polyester, and acrylic that borders on a belief that cotton is a miracle fabric.) They may rate that jacket as keeping you warm at zero - just remember that they didn’t say for how long it would keep you warm.

You really need to watch the quality of the stuff from Duluth Trading, Eddie Bauer, and other “outdoor wannabe” brands where looking like you go outdoors is more important than, you know, actually going outdoors. North Face and LL Bean are better about it, but you still need to be careful.

Yes, a puffy jacket should be puffy.