Is fluoride really good for your teeth?

Yes. Fluoride is essential in maintaining good oral hygiene and avoiding carries/plaque.
Yes. Research shows that Fluoride helps prevent cavities in children and adults by making teeth more resistant to the acid attacks that cause cavities. Fluoride helps rebuild (remineralize) weakened tooth enamel and reverse early signs of decay. When you brush your teeth with Fluoride toothpaste, or use other Fluoride dental products, you are providing a “topical” benefit.
Yes, definitely. Fluoride changes the chemical structure of tooth enamel making it stronger and more resistant to demineralization by plaque acids. Fluoride also has antibacterial properties, reducing the number of plaque bacteria in the mouth. Fluoride is very important for children due to questionable oral hygiene in some instances. And Fluoride makes teeth stronger during formation in children.