The reason many think of the restriction of no Eagle Projects for the CO is that before the 1990s, it was a restriction.
I became a Scoutmaster in 1984 and the Eagle packets then stated that the project could not be a benefit for the CO. It changed some time in the 90s and projects for the CO were allowed.
In our area, a project that calls for just painting, no matter how large an area, would not be approved. This is considered regular maintenance work. If the project included some remodeling, with the necessity of painting, then it might be approved.
Any routine maintenance work that the benefiting organization should be doing should not be allowed as an Eagle Project. While many do allow it, it is really make do work and rarely shows any leadership.