Why were the battles of trenton and princeton important?

The main importance is that this battles brought back the morale of the army and people once more started believing in the cause of the Revolution. This happened after the Patriots lost a couple of battles and the morale wasn't that high.

Explanation:

After the lost that happened during the siege of New York the cause of Revolutionary army seems somehow lost, and that is why Washington decided to cross the river Delaware and to try to defeat the enemies on their own ground. Not only that the morale was once more high, but they also managed to restore control of certain regions.

d. dr. francis collins