The buffalo bike is one that was specifically made for developing nations and the project prioritizes local assembly and repair, while the bike is designed to sacrifice weight and aerodynamics, instead offering heavier-duty parts like thicker rims, puncture-proof tires, high-capacity racks, etc. This bike has two chains to reduce the likelihood of a critical failure and an internal coaster brake hub which is more robust to the elements.

Your average low-cost bike isn't intended to be used in environments with rough terrain and high contaminant concentrations without regular maintenance, and especially older bikes with things like cup and cone bearings which are more susceptible to dirt getting in, thinner tires which puncture more easily, and nonstandard bits and pieces like derailleur hangers which predate the UDH standard.