The Temple vessels are not a secondary detail of Daniel 1.
Their transfer to Babylon opens a motif that finds its decisive development in Daniel 5 and its historical extension in Ezra 1.
At the beginning, their presence in the treasury of Nebuchadnezzar’s god might seem to attest Babylon’s religious victory.
But Daniel 1.2 immediately forbids this interpretation: it is the Lord who gives Jehoiakim and some of the vessels into the hand of Nebuchadnezzar.
Several decades later, Belshazzar has these vessels brought in during his banquet. He drinks from them with his dignitaries while praising the gods of gold, silver, bronze, iron, wood and stone.
Daniel explicitly interprets this act as a lifting up of oneself against the “Lord of heaven” (Daniel 5.23).
The kingdom is then numbered, weighed and handed over to other powers.
The path of the vessels thus accompanies that of Babylon:
they enter Babylon when the empire dominates Judah; they reappear when that empire is about to disappear.
Ezra 1 finally completes the movement when Cyrus returns the vessels so that they may go back to Jerusalem.
The course is therefore particularly significant:
Jerusalem → Babylon → judgment of Babylon → return to Jerusalem.
Through this material motif, the narrative expresses one of the fundamental themes of the book of Daniel: the visible defeat of the people of God is not the defeat of God himself. Empires may seize the vessels of his sanctuary; they never seize his sovereignty.