The main reason I use muriatic is because of it's low cost and easy availablity. I have enough brain cells to manage the risks with the product, so that's not an issue for me. (I also reload pistol ammo- make bullets from melted lead, handle gunpowder, AND I EVEN DRINK COFFEE FROM MCDONALD'S! and still have all my fingers, toes, and both eyebrows- go figure).
The alkalinity of my tap water is off the charts, and it's nice to add a relatively small amount of muriatic instead of 3 or 4 spa sized containers of decreaser, at about $6 each. Used to cost me over $20 just to balance the water. Now it only costs a few pennies, and I'm adding less "stuff" to do it.
But if I only had minor adjustments to worry about, I'd pay for the spa packaged decreaser products.
By the way, muriatic acid doesn't seem to freeze, at least in winter temperatures in MN. I forgot the container was outside since my last water change, and despite several below zero nights, it didn't freeze.
