A hospital plan pays for hospitalisation, surgery, and major medical events. It does NOT cover GP visits, dentistry, optometry, or non-chronic medication out of hospital; you pay those yourself. Most hospital plans still cover the 27 chronic CDL conditions because that's a legal requirement.
SA example: Discovery KeyCare Core, Momentum Custom, and Bonitas BonEssential are hospital plans. A 25-year-old paying R2,000/month is protected if they break a leg or need surgery, but pays out-of-pocket for every GP visit.