Does the Jack Wolfskin Jasper 3-in-1 actually keep you warm?

Hey everyone, I tried on the Jack Wolfskin Jasper 3-in-1 at a store and I’m unsure if it’ll actually keep me warm.

A few questions for people who own or have used one:

• Does the Jasper 3-in-1 keep you warm in real cold? • If it’s not ideal, what are good alternatives (preferably 3-in-1) with a slimmer fit and that won’t break the bank?

Also, are there any other budget-friendly options? I’m a size Small, Jack Wolfskin’s Small felt a bit large on me, while the Vaude 3-in-1 in Small fit well, but it’s quite expensive