A bridge helps to strengthen the prepared teeth and makes chewing and eating easier because they are fixed and can't come out.
Once you have a bridge fitted, you will have to take extra care of your daily hygiene regime to ensure it stays plaque free and that you can prevent bad breath.
You should replace missing teeth for a number of reasons. Your appearance is one reason. Another is that the gap left by a missing tooth can mean greater strain is put on the teeth at either side.