Survival Rates
Planting this way in a garden you would probably be much more concerned about how many will survive; whereas planting in the wildlife eat quite some of the plants – as later, when the trees (or whatever we planted) mature, the very same local wildlife will help spread seeds, so help recreate the forest.
If trying the method in a garden, probably best just to protect the plants whichever way you normally would and try and planting method as a time-saver (and back saver). However, you might want to think about whether there are other plants which can act as natural cover for the more delicate ones and whether you can plant seeds directly within or right beside them. Think of the cover plants as “bodyguards” rather than as “companions”… 🙂
However, even in garden situation, if you have plenty of seeds, and since the planting method is go quick and easy, you might not mind so much if some of what you plant goes to feed the local wildlife.