First of all, what exactly is a 3 season sunroom? It’s an extension of your home comprised of mostly glass and screen, but it’s only used during the warmer months (not winter). Eieihome.com has a great video highlighting some benefits of a 3 season sunroom and they also share some information about the importance of letting your home breathe.
One of the biggest reasons you would want a room with many screens is so you can relax in the comfort of your home and save on energy. Beat the heat by turning the air conditioner off, opening your windows, and taking a seat in your sunroom with a good book. That said, the spring and fall are also good times to rely on quality screening to get some fresh air and increase the comfort of your home.