There is a spiriritual law behind worshipping ancestors: anything or any thought you worship in this universe, if you do not worship God, the power of evil spirits will definitely befall and bind you.

因为那件事会带来的损坏非常地大！ 对拜祖先的事情先讲到属灵的原则：万物里面只要你拜的东西或者拜的思想也好，倘若拜的不是上帝，邪灵的力量必定会临到而捆绑祭拜之人。

youdao

Its origins lie in an ancient practice of worshipping nature and its guardian spirits by emulating natural sounds.

UNESCO: Culture

Music and dance was also used for important worshipping ceremonies or to seek protection from the ancestors and spirits before a hunt or battle.

BBC: Tribal culture survives in Taiwan