We notice a drastic reduction in the amount of chlorine (bleach) needed to maintain proper levels in the pools that we treat as opposed to the amount needed prior. I will admit that I am not a chemist, but I can't figure out what else could be contributing to the decrease in chlorine dosage.
Hard water is detrimental to many things (heat exchangers, pump shafts, SWCG cells, plaster, waterline tile, water features, etc.), and I see no advantage of maintaining a high CH level (anything up to or over 1,000 ppm). Arid conditions accelerate the accumulation of high ppm numbers, which just means that treatment or replacement must occur more often than less arid areas.
The only reason that I can possibly see for allowing such high concentrations of calcium is to temporarily save money. Continued disregard for these levels, if they indeed do or do not allow for easier propagation of algae, is playing Russian Roulette with your plaster and equipment. I'm not willing to take that chance for a few dollars.