You can use this structure to share your opinion or emotion with another person. 

Aren’t these cute?

Isn’t this weird?

This structure is very similar to saying, “This is (adjective), isn’t it?”

These are great, aren't they?

Although both are questions, they aren’t really open to all answers. With both structures, the speaker expects the listener to say yes. If you disagree, you can say so, but it may be considered impolite.