This article in The Guardian attributes the creation of the urban acupuncture movement to Finnish architect Marco Casagrande, but the central interview is Los Angeles architect and professor John Southern:
"Southern explained that the urban acupuncture approach treats cities like a living organism. Such micro-targeting, low-cost, democratic, and empowering tactics provide urban residents the much coveted green space that they desire without driving to a specific location. Although city politicians want to score points from the creation of enormous parks or even large building complexes that score a green certification, those projects often run over budget and even take away space that could benefit local communities in other ways."
Southern advocates for pocket parks over large-scale central parks, and a focus on streetscaping.