Q. Why do men wear nightwear?

Nightwear can be worn in other contexts besides sleeping. You can throw this on with minimal thought. You shouldn't feel the need to change into something just as constricting as a suit when you return home following a hard day at work. Consider trying a set of pajamas that you can mix and match instead. It's smart it'll make you feel great and it'll extend the life of your nicer garments.