Hard water doesn't damage your skin because calcium is "bad" for you. It damages your skin because dissolved calcium ions bind to soap, oils, and skin proteins, leaving a microscopic film that dehydrates the barrier and clings to hair cuticles.
A whole-house softener removes the calcium by swapping it for sodium. Effective, but expensive, salt-heavy, and discharges brine into the water supply. Not how we'd choose to drink water.
TAC media solves the same problem differently. As water passes through it, calcium and magnesium ions nucleate onto microscopic templates and form stable, suspended micro-crystals. The calcium is still there — but it's been physically restructured into a form that can't deposit on surfaces.
You keep the mineral in your water. You lose the residue on your skin.