The blessing of Eretz Israel is... Tzara'at?? (Talking Parsha - Tazria Mezorah)

This week we read about tzara'at (leprosy) - the part physical, part spiritual disease. Within tzara'at, there's also the tzara'at of the home - tzara'at habayit. Interestingly, the Torah starts the passage about tzara'at habayit with the very positive words of "When you will come to the land of Canaan, which I give to you for a possession, I will give you..."

One has to ask - why does the Torah use words that sound like a blessing? What's so positive about tzara'at of the home? And how does it actually teach us an important message for Yom Ha'atzmaut (Independence Day)?