Part of their appeal is down to their range of unique units. Of course, this means enemies must also adapt to keep up with your changing tactics.
This is because they do not have one focus but can shift it across the ages. The Chinese have a three-star difficulty rating, making them one of the tougher civilizations to use on Age of Empires 4. They also benefit from having strong war elephant units.
In military terms, they are excellent cavalry fighters and gain bonuses against mounted troops.