The text matters because of what it contains that no earlier Indian source does. The twelve places counted from an ascendant, the aspects between planets, the lords of the signs and the apparatus of horoscopic prediction are Hellenistic in origin, and this is the earliest surviving Sanskrit work in which they appear as a system. The title says as much: it names the material as Greek genethlialogy, and the text presents itself as a versification of an earlier prose rendering from a Greek original.
The older Indian astral tradition was not this. It was calendrical and omen based, concerned with the lunar mansions, the timing of rites and the reading of portents, and it continued alongside the imported system rather than being replaced by it. The two are still layered in Indian practice today, which is why a modern jyotisha chart carries both a Greek derived house structure and a lunar mansion scheme that owes nothing to Greece. So the work sits at a documented junction between two technical traditions, and says so in its own title. That is a rarer thing than it sounds. Transmissions of this kind usually have to be inferred from resemblances between systems whose contact is otherwise unrecorded, and the inference is always arguable; here a Sanskrit text states that it is rendering Greek material, which turns a hypothesis into a piece of evidence.