Flying a trainer kite is a great way to learn kite flying skills. It can also save you some money when you take kitesurfing lessons.
They have the following advantages
You can fly them in parks or beaches wherever there is wind.
They are fairly small (usually 2m) and not as dangerous as a 10m inflatable kite
They improve your kite handling and flying skills
They are easy to setup and launch, no pumping up is required
They are quite robust
They are quite cheap - about the cost of a single kitesurfing lesson at around AUS $170
You can lend them to friends who are interested in kitesurfing, and they won't get into any trouble flying them
They are great for kids and partners to get some experience with kite flying.
You may be able to use it in conjunction with a skateboard (landboarding) or skis/snowboard (snow kiting)
You can learn a many kite handling skills using a trainer kite and concentrate your lessons on body dragging, using the board and getting going