The consequences of this law fall into two classes, and both belong in the record.
For the church, establishment brought resources, legal standing and reach that no voluntary body could have achieved, and it is the reason a large proportion of the material in this atlas exists at all: the manuscripts, the buildings, the councils, the endowed schools. It also brought the state into doctrine permanently. Emperors called councils, exiled bishops, and treated theological dissent as sedition, because after 380 it legally was.
For everyone else, the law made religious difference a punishable status. Its immediate targets were other Christians, and heretic in Roman law from this point means a category of person with reduced rights. The older cults were suppressed within a generation. Jews retained a legally protected but steadily degraded position, and the accumulating disabilities in the same book of the Theodosian Code are the beginning of a legal tradition that ran for a thousand years.
The atlas records the law rather than judging it, but the sequence it belongs to is worth stating plainly: a community persecuted within living memory acquired the machinery of persecution and used it. That is not a peculiarity of Christianity, and later entries in this atlas show other traditions in the same position making the same choice.