Leaf Mold! By all means, pile it on. I can't say enough good about it
Humans can get by on a diet of milk and potatoes. Together they provide a complete protein. Although you won't die of starvation, there's not much vitamin C...perhaps scurvy will become a problem. A variety of foods will offer more of those vitamins, minerals and phytochemicals the body needs. Plants are no different, nor are the microbes in the soil.
We can not live on bread alone. Plants can not live on N-P-K alone.
Too often I see and here growing systems that reduce complexity to barebones necessities. The County Extension Service is notorious for helping people 'improve' their soil by prescribing how much synthetic fertilizer and lime to add in order to bring the soil up to recommended levels. Have a look at the
Garden Picture Exchange and see if plants are thriving.
Simplicity can grow a plant.
Complexity will grow abundance and nutrition in great diversity year after year.
Please don't misconstrue my zeal as bashing the idea of sand and sawdust. There are places in the world where it's the only thing available besides concrete and steel, which are VERY hard to grow anything in. In the absence of deep, rich, well drained loam in a tropical environment, using what resources are available and trying is better than doing nothing. From trying come learning. Learning develops an understanding of the myriad ways life works to promote more life.