A formal service book stays where the liturgy puts it. The Bohohlasnyk was built to do something looser: gather devotional songs, kanty, that could travel with worshippers into homes and gatherings the liturgy itself never reached, covering the feast days of the church year, individual saints, and penitential and reflective themes in language closer to popular song than to chant. That paraliturgical looseness is very likely why it spread as widely and as durably as it did.
The collection was reprinted again and again across the nineteenth century and into the twentieth, in Pochaiv itself and in Kyiv, Lviv and Kholm, well outside the single press and the single Uniate century that first produced it. Philologists took it seriously as source material in its own right: Volodymyr Peretts, Pavlo Zhytetsky, Ivan Franko and Mykhailo Vozniak all examined it, treating a book meant for singing as a document worth close scholarly reading, and mining it for what it preserved of an older, largely oral devotional song tradition. A collection built for popular, portable use, in other words, ended up mattering to two very different audiences at once, generations of worshippers who sang from it and generations of scholars who studied what they were singing.