Air Gap in exterior wall?

[ktmossman]

I'm dismantling my 2006 J4500 and I came across something I hadn't expected.  It seems the exterior fiberglass panels are not affixed directly to the structural stainless.  There is an aluminum cross piece that is channeled and creates a gap of more than a quarter inch between the stainless and the fiberglass.  When they insulated, the insulation is only the depth of the steel frame, so it leaves that gap intact.

I have to assume they engineered it that way intentionally.  The question is whether or not I care about keeping it moving forward.  My plan had been to use 1/8th inch EHP/CeraTex against the exterior panel and then spray foam to a total depth of about 2 inch (depth of the steel plus a furring strip).  But, if there is some inherent advantage in keeping the  air gap, I can re-think that plan...

Thoughts?