Packing with ice packs is a standard component of TTM, generally in conjunction with other therapies (chilled IV fluids, etc). It's also the easiest step to take in a prehospital setting, which is why we do (this is a thing I've done with maybe a dozen patients over the past few years). I'm not just making this stuff up, it's based on actual treatment protocols and algorithms.

We're talking about a naked, sedated patient (so they're already losing a lot of heat due to simple convection, and there's no heat being generated by skeletal muscle movements). The body's metabolism has slowed significantly, and it's producing anywhere near the normal level of "baseline" heat.

This procedure is initiated after the heart has been restarted[1]. You're absolutely correct that it's pointless to do it earlier, especially since the far more important thing is getting the heart beating again.

[1] This is known as "targeted temperature management" (TTM), and is part of the standard post-ROSC (return of spontaneous circulation) algorithm in ACLS (Advanced Cardiac Life Support), if you're looking for terms to Google.

the cold won't distribute at all ?

Those spots are not prone to frostbite, since the "coldness" gets distributed through the rest of the body very quickly (apologies for playing a little fast and loose with thermodynamics there). This is why they're used in the first place to cool the person quickly.

I don't know the exact implications, but I'd probably rather have frostbite or even lose a limb than have serious permanent brain damage.