Serge wrote:

The idea is certainly not new (Aleuts used it for ages)-

www.zyflex.com/store/products.asp?...

What are advantages and disadvantages?

How about that it's not sealed at the wrists or collar? When you think
about it, it's a poorly thought out piece of gear.

If you want a tuiliq, get one from Brooks or Superior. Another option is
one of the sealed skirt/jackets or tuiliq from Chillcheater.