They used to call those "track bikes" back in the day when I worked in a bike shop. Far better than a single speed Schwinn but really a specialty bike. The ones I remember were direct drive with no freehub so the cranks were always turning when the wheels turned.

I remember owning a one speed bike and thought what a great improvement when I got my first "10 speed bike", a Fiorelli racing bike. It was far easier to ride because I could usually find a comfortable gear for the terrain. I'd never go back to a one speed bike.