It's risky to travel some places with loads of cash though.  Was on an island of the coast of Mozambique once. It had one ATM that was broken.  Paypal saved the day as the lodge we were staying in accepted PayPal. So we paic them extra to pay some of the other activities. It was lucky as the of course knew everyone on the small island.

We kept some cash for when we were back on main land as we had to get someone to drive us out of there. Was fun negotiating as we had just the bare minimum abount for the drive. Since drivers didn't want to take us. One accepted in condition of no ac which we were fine with.

That country uses meticais, ZAR and USD in increasing order of preference.  But carrying lots of cash is not always advisable when travelling the way we were doing it. 

Anyway if ZAR is a preferred currency you know you've got it rough.  BTC should be useful there...