I'll cut to the chase. The study concludes low-carb diets are no better for weight loss and yes they're safe.....but, the authors bizarrely used a carb cutoff of 45% to define "low".
A diet with 45% of calories coming from carbs is not a low-carb diet and certainly isn't usefully comparable to one containing 20% carbs (and yet the authors did).
So sadly this paper doesn't help with the questions it set out to answer, but for what it's worth, my non-objectively quantifiable take on low-carb diets is that if they help you to control your intake, and you enjoy living that way, I wouldn't waste a moment worrying about safety. Of course if you don't enjoy low-carb life, please don't think there's no other way to go.
Reading this piece I could help but wonder, where, oh where, is peer review?