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It does not look like that helped to inhibit her powers, in fact, they grow stronger as she grows older and still, no matter how potent her Ice Powers are, they can be completely controlled if she only wears a glove. Also, plot wise, nothing important seems to have happened during the time she was locked in her room; she was put in when she was a child, she grows older, then comes out one day to be coronated.
So what was the point in locking her up?
After the incident with Anna, her parents were scared of her powers going out of control and hurting someone. The troll king warned them of dire consequences if Elsa doesn't learn to control her powers:
"Listen to me, Elsa, your power will only grow. There is beauty in it. But also great danger. You must learn to control it. Fear will be your enemy."
Her father, terrified of the idea, replies:
"No. We'll protect her. She can learn to control it. I'm sure. Until then, we'll lock the gates. We'll reduce the staff. We will limit her contact with people, and keep her powers hidden from everyone. Including Anna."
He decides that until Elsa learns to completely and safely control her powers she could be a danger to others, so he limits her contact with other people until she does. This also works to hide her powers from the general populace, who would react badly to having a royal with such a deadly, and uncontrolled, power.
Unfortunately, all this does is instill more fear into Elsa which drives her powers out of her hands. It wasn't until the movie's climax does she realize that love was the emotion that would control her powers.
I didn't take it as she was locked up, but rather that, because of the conversation between the troll and the king, she was hiding, shutting everyone else out to avoid hurting them.
