Its a personal choice but I will tell you my reasoning.
My garden is a raised bed and I use no till. My yard is a small city lot with no room for a compost pile, no lawn and no trees (I live in the desert) so all my additives are bagged from the BigBox store. I don't layer my already decomposed material in the fall because it would all blow away in the wind (often 50+ mph) before planting time in the sping. I do plant peas in winter but I pull them and add them to my daughter's compost pile.
You could plant a cover crop and leave it to die and decompose, just move the dead plants aside and plant.
When I had the room for a compost pile, chickens, a lawn, trees... I used the no till method but used my compost pile because I don't think the direct layering is an advantge. In fact, I think it caused me more work because I had to keep moving un-decomposed material aside and planting while waiting for it to decompose. Why bother? All that stuff was happening in my compost pile and the chcken manure made some great soil. But it took a year (I had two piles, one for everyother year) of mixing and watering before I was happy with the results to use in my garden.
@mnoasis,
@gardenfish, anyone else care to add?