Those are two different benefits and a policy can cover one without fully covering the other. Emergency evacuation generally means transport to the nearest adequate medical facility. Repatriation means the arranged return to your home country or another agreed location, usually after initial treatment and stabilisation. Check both limits separately rather than assuming one number covers the journey home.
Worth asking your insurer: who decides where the patient goes, at what point repatriation becomes available, whether a medical escort is covered, and whether the policy pays for a travelling companion or dependent children to travel too.
South Georgia's permit also requires cover for repatriation of mortal remains if a visitor dies there. That's a separate benefit again and it's worth confirming rather than assuming.
There's a related question about where evacuation even starts. Some policies define it as transport beginning only once you've reached a port or hospital. On an expedition, the sequence can be onboard stabilisation, a Zodiac transfer, another vessel, a remote airstrip, a charter aircraft and then a ground ambulance. Ask how coverage applies while you're still aboard in remote water.