Footprint and Board Layout Fit
For a board layout engineer, the 0.100" row spacing and 0.100" pitch create a symmetric grid that routes easily on two-layer boards. The 0.135" post length is typical for standard PCB thicknesses (0.062" to 0.093") — the solder tail protrudes enough for a reliable through-hole solder joint without bottoming out on the opposite side.
Tin-plated phosphor bronze contacts resist corrosion in normal indoor conditions but are not recommended for repeated mating cycles beyond a few hundred — the tin finish can fret under vibration if mated/unmated frequently.