The through-hole termination gives a stronger mechanical anchor than SMT, important when the cable sees repeated flex or strain.
The 3.20 mm post length (0.126") is standard for through-hole soldering to a typical 1.6 mm PCB; the board guide feature helps align the header during wave solder assembly, preventing skew from the solder wave.
No official cross-reference or pin-compatible alternative is listed from Molex. The 172310 series includes other position counts (2 to 10 circuits) in the same pitch and orientation, but a different position count means a different board footprint.