Honestly, to me buying bac. water is just like buying syringes. Yes, you can re-use syringes and yes, you can boil the water and do it that way, but Bac. water, just like syringes, can be bought in bulk, and cheap... sooooo why not just make life easy?
I would be pretty annoyed if every time I had to mix hgh I had to boil water. It's much easier for me to just draw from the btl of bac water sitting in my fridge and mix.