I too use use both types of fertilizer, relying primarily upon synthetics. I use dissolved organics (similar to manure tea) to supplement. I like to think that by varying products I cover all my bases.
The above statement is true, but only if you're growing, as Naka did, in at least 50% organic soil. He used soil, mulch, and leaf mold to build a good micro-organism base and create a living soil.
The micro-organisms in the organics break down the organic fertilizer to basic components that the plant can readily take up.
If you're growing in inorganic media you are essentially growing the plant hydroponically. Not much miro-organism activity going on in the media.
This is a good point, modern bonsai 'soils' are very lean, often bordering upon completely inorganic. In my climate, I use about 15% bark, at the most, for deciduous species, no other organics. Others, Pine and Juniper, are in 100% inorganic For my trees in such a medium I avoid solid organic fertilizer. I have experimented with solid organics in the past and found that they break down and clog my substrate.
I even went to the trouble, and expense, to manufacture my own fertilizer cakes as seen in many books. I was pleased with my efforts until I began to use the cakes. They became soggy almost immediately, collapsed into ugly lumps, began to clog the soil and attracted fungus gnats. After that I broke the cakes back down to a dry powder and found that I had all of the same issues except they were not so unsightly. Now I dissolve it, along with some compost, and use this as a tea, excluding the solids, in addition to the synthetics.
I don't use synthetics in the garden or landscape, because it is not necessary, but have no qualms about using it in pots.