Can a double loop cable stand up to cable cutters?
Short answer: no.

I've cut a 10mm stranded cable using normal straight-jaw wire cutters in under a minute. 4mm I expect I'd cut in one go, in whatever time it took to put the side-cutters onto the cable plus a second. The 10mm cable I cut with sidecutters because that's the tool I had handy, so I just nibbled a bit of the plastic cover away and then cut one strand at a time using the very tip of the jaws. It was mildly tedious, and the leverage was all wrong for the first few. Once I'd cut about a third of the strands I could work two or three uncut strands into the jaws a bit more and cut them more easily.

As you point out, a stranded cable is trivial to cut with the right tool, and even a very heavy one (more than half an inch thick) can be cut with hand tools in a couple of seconds. Small versions of those cutters look like any other pair of pliers and a good set will cut most bicycle cable locks in seconds. A heavier set looks like bolt cutters and are usually rated to 3/4" or 1" cables. Or you can buy battery powered versions of those for more money.



An armoured cable is harder to cut because there's steel segments surrounding it, and usually they're an inch or so in diameter specifically so you need a physically larger tool to cut them. But the segments can usually be crushed by a bolt-cutter style rope cutter and then the internal cable cut.

The other obvious answer is a disk grinder. They're loud and obvious, but these days battery powered grinders are cheap and readily available. And they're quick - under a minute, likely under 10 seconds for most cables.

Most bike thieves will have one or more of these tools available, and the trouble with the pocket-able plier shaped ones is that they're very easy to carry just in case.