Seems like the 1.5% only applies to purchases using the physical card, not online purchases using a virtual card. I ordered something from Europe and was surprised to find that the 1.5% extra euros I loaded onto my card was still on the card.
Confirmed on the 2022 SBK fee schedule:
Thank you so much for this! It helped me make sure that I only have to take one day of paperwork to apply for the importers code in Cape Town. The "letter of intent" bit, in particular, isn't clear from SARS website. There were two things I had to do extra, but luckily there was a police station...