In the eyes of her neighbors, Israel was at a disadvantage. Israel said her God resided in the temple (or tabernacle) but there was nothing there to indicate that He did. At least in pagan temples and places of worship there were images representing the gods being worshipped.
Not so in Israel.
The writer of Psalm 115 picks up on that difference to make a point. If the idols were actual gods, they were fairly impotent. Lifeless in fact. If, however, the idols were simply representations, then they still represented gods who could not speak, see, hear, smell or move – because the idols couldn’t do those things.
What a difference between them and the God of Israel who could not be “represented” by anything. Remember that God had forbidden Israel to make any likeness of Him.
Because no “likeness” could do Him justice.
The result of worshiping lifeless gods is always simply and only death. But the result of worshiping the God of Israel is life. Only He provides protection, increase and progeny. Because only He lives.