The tradition was started way before I was born...my Mother's family always sent presents to each other as they did not live all that close, and the mail was not always that fast so presents would usually arrive between Christmas and New Years. It just made the fun last longer.
Even when my children were small and grandma and grandpa lived in Florida, presents arrived between Christmas and New Years but then it was planned to be that way...Cards were just as slow...
I like the tradition as it gives a whole week to enjoy the holiday, and to meditate on it's true meaning. Christmas is not just about the presents, and the food and the fun..It is much more than that. The candles in the centerpiece are lit everyday starting with Christmas Morning and ending January 2nd. It just seems to make the celebration more meaningful.
JESUS IS THE REASON FOR THE SEASON, CELEBRATE HIS BIRTH