To clarify, for people who have no idea why there is needed a certified for kayak, we have placed a comparative statement.

You also would not drive in a car without a steering wheel and no brakes?!
For driving a car, motorcycle and moped, you need a driving license. For the larger pleasure ship you need a certificate but what do you need for a kayak?

The danger of incompetent and hidden risks!
To paddle straight with a kayak or canoe is already an art in itself. Often you see beginners paddling uncontrolled on the water. In fact they are floating around out of control. In still standing water it doesn’t have to be a problem, although a kayak is unstable and always can flip.
Once people going into the current, the kayak will sail itself. You will see the shore passing by and you need to have some techniques to control or stop the kayak. If you don’t control this techniques, you paddle rudderless, without brakes and you have an actual change that any danger can’t be avoid.