It allows you to set ticket prices differently for different groups ie Adults, Children Student, senior citizen and families .
However, you can only add ticket types at the event level. For recurring events, if you set it in the parent it gets carried through to child events.
But if you have a lot of different events where you want to use ticket types, you have to manually add the ticket type to every event which is time consuming and prone to error.
A better way would be to set up ticket types like categories or locations. You could setup all our ticket types and then just set up for your events, just like you do with categories and locations.
Having this facility would be a big saving in time with less chance of errors