Travel, Teach, Live in Japan
It is good to have stamps to identify yourself!
Not only in Japan, but in many other Asian countries, people use stamps instead of signatures to identify themselves. And most of them are made by hand, so that each stamp has different shapes of letters - even if the names are the same, they will show up in different shapes.
Of course, all signatures have different shapes, too. But even your own hand-written signature might be different from your original signature - depending on your conditions.
Also, it is fun to choose material for stamps. Ivory, Agate, and Jade are popular and more expensive than others. Get one for your memento!