Anecdotal mentions of hard water providing health benefits are always questionable when a lack of a peer reviewed study or trials, population studies etc, fail to materialise, or how any newly supposed findings of other benefits are concluded, and from what sources?
Any global scientific studies, and none have been forthcoming to date, would have to list a control group, background health of the group, diet, the level of water hardness, (has it got little or no minerals in it like Volvic water at 10 ppm calcium or is it rock hard like Ballygowan with 100's of ppm calcium), and what if any effects are seen over a period of time, then repeating the study to give duplicatable results.
We know hard water causes havoc with pipes and plumbing, heating elements, showers, washing machines, dish washers, kettles, etc, right back to the steam age of boilers getting scaled up on steam trains, shortly after which ion exchange water softeners were invented.
The Battelle Memorial Institute Study on water hardness has been a successful multi million dollar year long study of the effects of hardness targeting to the nearest 1% values how much limescale builds up on pipework for a given level of water hardness, and the percentage heat losses using gas boilers, electric heating elements etc.
Water softeners have become such a fractional cost of what they used to be, often for apartments as low as three or four hundred euros, and have become so more efficient with volumetric metering controls, that their pay back, not only falls within one or two years in some cases, but are now heralded as one of the most greenest devices on the planet for carbon footprint reductions, and certainly they now have the greenest domestic credentials in the household, with the energy savings provided.
Over 90% of owner apartments are allowed to install water softeners, I have not heard of many who are not ?