^ How fast? ^
I wouldn't consider my cheap folder to be dangerous at all, as long as the tires stick, it can be ridden
just as fast as any other bike. (on smooth pavement)
Sure its not as efficient as a traditional 700C bike, it can fit in a suitcase, and for me that is a worthy trade off.
It has paid for itself many times over in terms of baggage fees that most airlines charge for bicycles.