Should I add a foam camping mattress to a bugout bag, in winter in a moderately cold climate?

I could replace a foam mattress with a large sturdy plastic survival bag.

I can use that survival bag also as a bivy bag, spare poncho, tarp, writing paper, floating device, etc.

That survival bag is made of plastic foil. It is much more compact and less conspicuous than a foam mattress. that is tied on my bugout bag.

I could fill this plastic bag with dead leaves, hay, cardboard, rags, etc. in…

Foam mattress for bugout bag?