A hospital plan pays for hospitalisation, surgery, and major medical events. Most do NOT cover GP visits, dentistry, optometry, or non-chronic medication out of hospital, so you pay those yourself; a few add an MSA or limited day-to-day benefits. 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 most GP visits.