The driveshaft requires less maintenance than a chain. That is however the only advantage.
The disadvantages are many. It’s harder to fix a flat. It’s much heavier. The bevel gears are expensive, or if not, of such poor quality that they wear out quickly.
Knowing all this why would anyone build a driveshaft bike? Fear the grease. That oily chain turns many people into screaming dirt-o-phobes.
On the other hand there is this mythology that cleaning and lubing a chain is a complex and exacting ritual that should only be performed by mystics in denim monk’s robes.
Meanwhile back at the cute little bike pictured above; the opening bid of $59.95 and buy it now price of $99.95 are much too high.