What are some good reasons why a person should practice casual nudity at home?

There are plenty: no need to turn the AC on in summer, less chance of staining clothes while cooking or cleaning, less need to do laundry, more comfort, no time wasted changing from street clothes to house clothes or to sleepwear. I am almost never clothed at home.

I wasn't aware that I needed a 'good reason' to take off my clothes in my own home. 

The first question is why not? Their home. They can dress or not.