Non-geared is an incorrect term. A bike without gears won't go anywhere or is direct drive like a penny farthing.
You mean multi gear vs single speed bikes. Multiple geared bikes were invented to make cycling easier, more efficient and faster. Unless you only ride for short distances on flat roads a multi geared bike is highly recommended.
That being said a current fad is fixed gear and single speeds. They're fun to ride but I wouldn't want one to be my 1st or only bike. And heck,, if you wanta single speed - simply don't shift!
