Not all of my matches actually show leaf hints at the top level. I will go and review a match and it will pop up with a shared ancestor hint when it did not have a leaf showing.
The system is a dynamic one, constantly searching and matching trees. As people change their trees, that will change the matches and either give or take away leaf hints. (I had a match to someone, but their tree was linking a person to a set if parents incorrectly. When they corrected their tree they no longer appeared on my leaf hints.)
Give it time. You may or may not ever get a large umber of matches. It requires other people to take the test as well, and many are not interested, or are not interested in posting trees.