I did not know that. That’s a good reason to choose it. I used to be concerned about water absorption back in the 70s when brake fluid turned dark after one year, was black after two years, and started forming muck at the bottom of the reservoir after three years. Then I bought a new '98 vehicle and year after year the fluid stayed clear. Something has changed, I says to myself.
One thing I knew changed - the master cylinder top used to have a hole in it to let air replace the lowering fluid level, then they came up with a diaphragm to keep it sealed. So now it’s a totally sealed system. That’s what I say. Everyone else on this forum says air infiltrates the seals, but I remain unconvinced.