Yes, travel insurance is genuinely important for a safari trip through Kruger Mpumalanga Airport, and the honest core of the answer is the safari itself rather than the airport or the surrounding towns. Most travelers flying into MQP are heading straight into Kruger National Park, a private reserve, or the nearby gateway town of Hazyview, and wildlife-viewing by vehicle or on foot carries a different risk profile than an ordinary city stay.
Clinics near the airport and around the park handle routine issues, but anything serious is typically stabilized locally at most and then evacuated to Johannesburg, the region's real major hospital hub, a short flight or drive away depending on where in the park you are. Confirm your policy covers medical evacuation from a safari lodge or remote camp specifically, since that transfer is the part most likely to involve real distance and cost if something goes wrong deep in the reserve, well away from any sealed road.
Kruger and the surrounding lowveld are a known malaria area, so check that your own preparations and your policy account for that general risk alongside standard travel cover, and confirm your policy covers wildlife-related injury if a walking safari or game drive is part of the itinerary, since some general policies treat close wildlife encounters differently from routine outdoor activity, sometimes requiring the activity to be named explicitly.
The wet season, roughly November through March, can affect road access to some more remote camps and lodges within the park, occasionally delaying transfers between camps or out to the airport itself. Keep any lodge or clinic paperwork, incident reports from a guide, and receipts for evacuation or treatment, since claims from a safari trip rely heavily on documentation from the lodge or operator as well as any facility reached afterward, more so than a routine city-based claim.