The small one is the improvement to people's health that follows from the widespread adoption of the microfarm as a significant food supplier and contributor to livelihoods:

• Produce is fresher (very short plot-to-pot time) and so retains more of its nutrient qualities
• Fresh vegetables, fruit and milk are more affordable as consumers who are not microfarmers are more likely to be buying from their neighbours who are, rather than from supermarkets supplied by the Big Hectare Farmers, and so consume more of them
• The combination of the above is good news for those living with HIV-AIDS; anti-retroviral therapy can only go so far in extending their lives. It is the unavailability or unaffordability of good quality food that now makes this disease life-threatening for the poor
• The very labour-intensity of microfarming keeps the microfarmer fit. Not for him or her are the modern diseases of obesity, diabetes, hypertension and heart disease such a threat.

The large one is the improvement to the urban environment that flows from the sudden realisation that there is no such thing as "rubbish" any more. "Waste" has value. Even "waste land" has value - especially in cities where such places often become the resort of criminals and sites for illegal activities. Making such places available to would-be microfarmers will certainly tidy up a neighbourhood. Meanwhile, the rubbish that was dumped there will find its way to the compost heaps of or be used for mulch by dozens of microfarmers round about. And now that "rubbish" is seen in a different light, it becomes more profitable to sort it, with the non-biodegradable fraction going on to recycling plants and the rest going for compost.
As for the Big Hectare Farmers, the only advantage they may have are the profits and subsidies that their farming generate which enable them to pay for the private health insurance needed to treat those modern diseases and the golf club membership fees needed to maintain good relations with their bank managers.