I like your points and this thread, [MENTION=31569]SurrealisticSlumbers[/MENTION].
Here a some I've thought of, some of them closely-related or just re-stating your points from a slightly different point of view.
1. The food is fresher, and that usually makes it taste better. I wonder if there are nutritional benefits to eating certain fruits and vegetables within a short time of harvest?
2. Tastier, more nutritional or just personally-preferred varieties can be grown. Extra-sweet varieties of sweet corn are great examples of this and the first point.
3. If a large garden, more like a mini-farm, is used for providing a significant amount of food, it can be planned to be very self-sustaining in both resources and finances. This includes providing its own compost and saving seeds for next season. The biointensive method teaches this approach. Much of it isn't practical for the average backyard garden, but some of the principles are. More info:
http://www.growbiointensive.org/PDF/FarmersHandbook.pdf
4. There are many approaches to gardening, and there seems to be a least one approach which will suit most people's needs. It's also great for people like me who like to try many approaches! One of these approaches is no-dig gardening, and this contrasts nicely with the "double-dig" approach of the biointensive method. I think many don't garden because they don't like to dig, maybe because they have back problems, or they don't want back problems. No-dig involves just throwing down a bunch of compost, and then topping it off with 1-2 inches every year. I also suspect that it could be combined with the biointensive method for a bit less work-intensive gardening! More info:
Why No Dig - No Dig Organic Gardening
5. You control what substances are used on the garden. There's usually a less biologically-alarming alternative to solving most gardening issues.
6. Gardens teach kids and adults about so many aspects of life which have been obscured away by modern life, such as:
Self-reliance
Where food comes from
The work involved in providing that food
How the weather, climate, and environment affect that food and life in general