The interesting part could be the difference in how you traded. If you traded back and forth between Rands and BTC then I imagine the accumulated profit/loss on those trades has a clear tax implication, whereas if you traded between BTC and other cryptos, for e.g. on a foreign exchange, things probably get murkier. I guess the question is whether every trade to cash from BTC ON the exchange is the same thing as withdrawing cash from the exchange.
SARS is essentially treating most BTC sales as a realisation of assets incurring CGT (like selling Krugerrands) although if you're demonstrably a trader then the profit is liable for income/company tax. But the question will be whether buying BTC once for cash, sending it to another exchange somewhere and constantly trading BTC/ETH, BTC/LTC, etc etc resulting in an increase in your overall holdings and sometime later returning it as BTC to Luno and cashing it out in a single transaction will be construed as trading or investing. And then actually providing a record of those transactions - working out the prevailing prices at the time, exchange rate, etc etc, would be an accounting nightmare.