Gen6 outback. Low profile snow cables on all four wheels or only fronts?

The cables meet and exceed SAE class S clearance reqs for the outback. Some people give the unhelpful answers of "don't drive", "get snow tires", and some say the ignorant "you can't use chains on a Subaru" these aren't chains, they are low profile cables. That said, the manual says to put them on the front wheels if needed. Why not all four?

I feel like I should be able to do all four of if keep speed under 40 mph, especially if I drop the pressure to like 10 psi under what the door says sticker says. I have all weather/all terrain tires on there right now, but if I wanted to use chains I don't see what the big difference there is between low profile cables and a roughish forestry road on the CVT or the differentials in terms of bumpyness