That 500 mV of receiver hysteresis gives it decent noise immunity on the serial lines, handy when the cable runs a few meters across a factory floor or through an outdoor cabinet.
Field-swap reality: package, orientation, and what is in the kit
The 16-SOIC narrow body (0.154" wide, 3.90 mm) is a common footprint — you can hand-solder it with a fine-tip iron and a steady hand, no hot-air station needed. If you are carrying a field kit, toss in a few of these; they swap into any RS232 port that expects a MAX232-class part. No lab, no bench — just a clean tip and good light.
No last-time-buy notice, no end-of-life countdown.