The idea is fantastic, and I for one think its a good part of a safe "Crypto portfolio"
Without going into my personal business details too much, I can tell you that my crypto business is basically doing something like this
1.Direct monetary investment in two-three large cryptos (e.g. Buying coin directly and saving it)
2.Mining myself in *2* crypto currencies, one to horde coins directly, and the other to mine for money, to cover mining expenses (this mines most profitable coin / day on a day by day coin switch)
3. Paying for hosted mining from a *hopefully* more reputable BTC mining company, for a flat out us$contract.
This way I'm spread betting my risk, and although it might turn out less profitable than investing in one avenue only, it also hedges the risk, which is important for me.
My 2c
(On that specific gumtree add -- tread carefully. The math is super optimistic, since he essentially assumes that his mining rate is his WU, which its not. AKA his pool won't see what his pc says he is mining. So for his R1000/month example, I would venture your hashrate effectively will only be around 500. Which currently works out to us$95 per month, BEFORE any difficulty increases. In other words I feel you will lose money/possibly only break even.
The magic number with mining is the DIFFICULTY. The other day the difficulty jumped 20% in 24h. Thats instant 20% less income. No warning, boom. Try work that into a business plan.
