Originally Posted by Trakhak

For those scoffing at the idea that the shoes In question are cycling-specific in any meaningful sense: every pair of non-cleated cycling shoes I've bought has had some kind of reinforcement in the soles that made them comfortable for long-distance riding. Very much like cleated cycling shoes, though in some cases with a somewhat more flexible sole.

Most non-cycling-specific flat-soled shoes I've used were OK for cycling maybe 10 miles or so but became increasingly uncomfortable over longer distances.

At least that was the case with traditional toe-clip-style pedals. Shoes with reinforced soles are probably less crucial if you ride with modern flat pedals.