Some of the advantages of letting them roam your yard:
With all that room you practically never get behavior problems when they are out there. Some of this benefit depends on how tight your coop and run are.
Your feed bill goes down. They forage for a lot of their food instead of you buying all of it. Some people like the eggs better when they eat all this varied stuff.
They are on bug patrol. The numbers of some annoying insects will drop, ticks for example.
If they can catch them they will eat small snakes, frogs, mice, and other small creepy crawlies you might not want around.
Some people get a lot of pleasure watching them roam in that setting.
Some disadvantages:
They poop everywhere they go. You may fine poop on your back porch, yard furniture, or just where you or the kids want to step.
If you have landscaped areas or a veggie garden they can eat the veggies and scratch the landscaped areas really badly, especially if any of them are mulched.
They may or may not hide a nest on you. You may not get all the eggs.
They will probably dig holes for dust bathing.
Depending n the size of the yard, your fencing, and such they may visit the neighbors. The neighbors may not be happy.
They are more vulnerable to predators. Some people free range for years and never lose a chicken to a predator while others can be wiped out as soon as they try. The increased risk from predators is pretty high but you just don't know what, if anything, will happen or when it will happen.
It sounds like you are in suburbia. You may need to build some fences to keep them out of certain areas of your yard.
That's all I can think of this morning. Some people do supervised free ranging, just let them out when they can be out there with them. That way they can help minimize the damage and provide some protection against predators.