These are among the more delicious of cactus fruits. Scripps News has the whole thing covered.
Among the most promising fruits for arid-zone American gardens is the apple cactus, Cereus peruvianus. This large, branching treelike columnar cactus produces some of the most delicious and beautiful fruits for gardens….
Due to the fact that the apple-cactus fruit does not have spines or glochids like that of the common prickly pear, it makes a far better residential fruit plant….
Whether you live in city or country, apple cactus is a great choice for drought-ravaged regions.
This article mentions that they are pollinated by bats, but only in passing. In fact, these are the notorious night-blooming cereus. The blooms are open one night only, so you have to have more than one plant happen to bloom the same night, and then you have to have bats. Now here in Berkeley, there are plenty of bats, but only up in the hills and not down here in the flats where the nursery is. So we do not get fruit. This is a problem with urban areas.
So I disagree with the conclusion that this is a good fruiting plant for drought-ravaged cities.