I think anybody starting out in exercise, for example, running probably get a similar effect to HIIT until they build up their endurance.
They run for a bit, walk for a bit, run for a bit, and finally walk. That, for them at least, is HIIT! Until they adapt to it and "progress" to using their aerobic energy system.
So hell yes running can help someone shed fat initially. The problem is, and if you have seasoned runners in your area(I'm being diplomatic) you'll know what I mean, they don't push themselves(That's assuming that they started running(probably on the 2nd of Jan) for the purposes of shedding fat), not to mention the terrible postural positions, arm carriage or lack there of, etc. Sprinters on the other hand...
Once you get in to that comfort zone that allows you to pretty much run at the same pace for seems like ever - you've obviously adapted. You've already gone thru the energy systems to get to the one, in my opinion, that's the least optimal for your goal. Despite this; "Aerobic energy system is the only system to use fat as an energy source" - it gets skewed and is assumed then that for optimal fat loss one must run or do steady state.
While yeah that's true, we do have access to fat stores during steady state, it's not quite as simple as just running or cycling or rowing....and that's even without mentioning all the info above on catabolism, whether cardio does decrease or increase myostatin and so on.
Simple adjustment to running which makes it effective for fat loss - get out of your comfort zone and up the pace, in other words, fartlek it.