South African passport holders can request a visa on arrival at Bole International Airport if they have not had the chance to apply for an eVisa beforehand. However, there are various drawbacks to the Ethiopian visa on arrival.
Travelers have to stand in line to apply at border control and deal with the application paperwork there. South Africans with an eVisa can avoid waiting around and wasting time applying for a visa at immigration.
More importantly, the eVisa brings the peace of mind of having an approved visa before traveling.
The visa on arrival runs the risk of having the application denied at the Ethiopian border.
In this case, you will be forced to buy a flight home without being allowed into the country.
For these reasons, the eVisa is considered the better option in most cases.