This is very interesting stuff. I agree that plaster isn't great. Mine has etched, scaled, cracked and the black has faded to gray in places. TFPC from day one, although I did have some curve on managing CSI early on. Our water is very prone to scale but started out with low CH, 150-160, so it etched early on and then flipped over to scaling once CH got up. Although, it has been pretty well under control since 2013.
So, does this stuff have any flex? My pool has a few cracks in the plaster from soil movement over the years. All 1/16" or less. One leaked 3 more did not. PB stuffed pool putty in the cracks which has worked fine. The crack that leaked was from 2012 and it still doesn't leak, or at least not enough to count.