Hindu and Buddhist practice put sandalwood to work in ways that have nothing in common beyond the wood itself, and reading them side by side is more informative than reading either alone.
In Hindu practice the ground heartwood becomes chandan, a paste applied to the forehead as a mark of blessing and smeared directly onto temple images as an offering the deity is understood to receive on the skin, not only as smoke in the air. This is a tactile, applied use that the incense stick sold in the West barely represents.
Buddhist practice runs in a different direction. Beyond burning it in temple and funerary rites, sandalwood is a favoured material for mala, prayer beads, worn and counted rather than burned at all, so the same tree supplies a wearable object of daily devotion alongside its role as smoke.
Japanese kodo names sandalwood byakudan and ranks it, with agarwood, as one of the two great woods of the incense tradition, heated on ash rather than burned to ember, judged and discussed rather than simply enjoyed.
The tree itself cannot keep up. Santalum album, the most prized source, was harvested hard enough that twentieth-century India placed it under state monopoly and strict export control, and CITES listing followed; most sandalwood sold today is Australian Santalum spicatum or is not true Santalum at all, a scarcity that sits uneasily beside how casually the wood is still described as an everyday incense.