Metal braces help correct dental crowding, they reduce the chance of damaging your prominent teeth and they make your front and back teeth meet evenly.
The braces do this by applying pressure to your teeth so they'll move and realign but they can also move your jaw as well if the wire is tightened or rubber bands are used.
This orthodontic treatment allows for better control and more accurate teeth movement in more complex teeth straightening situations, especially with teeth rotation.
Metal braces are incredibly durable and are less likely to cause discoloured teeth than Invisalign if you are not disciplined with your routine.  They can also improve your overall dental health once your teeth are straight they are much easier to clean.
The cost of metal braces can range between $3000-$6000 and are typically comparable to Invisalign leading many people to choose Invisalign if they only have mild-moderate straightening needs.
This is also because Invisalign clear aligners outweigh the metal braces in benefits for their appearance, diet, and amount of time they're required for.