In Countries where people fill their own tanks they do ring their own groceries. It is very Clever, you put in in the trolley, And the items have frids and whala the whole trolley scans itself you only pay, And if you have a card or a smart phone you do not even need a cashier!!
I shop with one of those. Walk through the store, scan the items I want, put them straight into their bags and then walk to the check-out to pay. No standing in queues, no waiting in line.
However, they do a random spot check every now and then when you pay to make sure you've scanned all your items.
Self-service is definitely faster, more efficient and a significantly better alternative to wasting your time in a queue.
Here you also fill up your own petrol tank, pump your own tyres, replace your own oil and check your own water. If you can't do that, you don't get a drivers' licence. Fairly logical, I'd say. If you can't do that much, why on earth should you be driving a car?
Granted, there's also functional (and safe) public transport for those who don't want or need a car.
The only benefit there is to having petrol attendants in South Africa is that it creates an income stream for poor folks who can't do anything else. And, honestly, I think that's a noble intention.
However, that's also why I look at unions striking and can't help but feel that they're shooting themselves in the foot.