I have picked up a few, just for show not for use.
A couple of years ago, we went to visit a friend of my husbands in Baltimore and also went to Washington, DC. She buys keychains from every vacation they go on and place them on her Christmas tree to remind them of their past vacations.
Needless to say, I thought it was a great idea so have been doing the same. I love Christmas ornaments as my Mom only had a fake white tree with blue bulbs. We lived in California and she missed the snow. I have over 400 ornaments on mine, and still growing!! :) :) :)