Beware, this is not entirely true. For one, Visa benefits are not equal across countries and typically we are not as covered as in the US. Do not use this document for reference - it is for US based cards and shows dollar denominated amounts. For US cards, travel insurance, car rental insurance, even price matching refunds (if you buy a product and a short time later it goes on discount) are quite standard. In my experience with SA cards, banks seem to opt into which of these benefits they wish to include from Visa.
In fact, most entry level credit cards in other parts of the world are free of monthly fees too - because cards are so lucrative to banks on interchange fees.
For another, Discovery is the first instance in which I have actually seen the inscription "Visa Signature" on a South African card, despite other banks having similarly tiered accounts. Best practice is still to confirm these benefits with your bank, before you get caught in a situation where your expectations don't meet the reality. I called into FNB a year ago only to realise that their card didn't even have a rental car insurance waiver associated.