I bought my Dahon Speed with an intent of converting it to drop-bars.
Drop-bars are the only kind of handlebars that I like.
If I'd wanted brifters, I could've changed to cantilever brakes.
Often examples with narrow tires are shown in the context
of folding road bicycles. Other than on a pristine racing track,
such as a velodrome, I wouldn't want such narrow tires.
The 20" wheels have a disadvantage to larger wheels when
you have to roll across bad surfaces. Having 50mm tires,
inflated to moderate pressure, feels a lot more reassuring
when you're riding small-diameter wheels at road-bike speeds.