a good set of points. And what the social practice art community--most of whom fucking hate that term and will throw their milkshake at you if you call them that--is achieving is more multi-layered.
The experience of the social interaction/engagement is genuine and in real-time. (For the good artist. There are a lot of posers, just like in any art community) The only difference between "social practice art" and plain old life is that this sort of artist
1. spends more time thinking about novel modes of social engagement (which is both an interesting effect of and comprises the art itself)
2. documents the work for a greater public art community. These artists are constantly struggling to achieve less intrusive methods of documentation, but as you can imagine, there's only so much they can do. Some of them do it clandestinely. And then the trick is how to make yourself forget about the documentation during the course of interaction. But I don't believe it's all that hard, actually. In any case, the discussion about the documentation's ruination of the raw artwork is pretty hot and heavy amongst these "types". If you ever want to insult one of them in the worst way imaginable, compare their work to that of "the spectacle" as described above. You've never seen anybody blush so fast with pure unadulterated rage. But they're such nice people all the rest of the time. ;)
The aspect of the art (or interactions, rather, depending on who you're talking to) being genuine means that the primary and time-based audience is thoroughly moved and touched in ways static art never could ever hope to do, and the ideas or memes are more thoroughly implanted in people's minds, and the ideas spread like viruses. When's the last time a painting has done that? Well I'm personally very moved by Jenny Saville and Egon Schiele, but with social practice or whatever you don't want to call it, the sensation is more pervasive and inescapable.
The artist him/herself is moved and changed by inputs and thought patterns from the organic Other, rather than by a system including only him/herself locked away from people and merely imagining them when it's necessary to do so.
I don't know... I've been thinking about street theater lately.
It's the last form of real artistic expression available today!