no reds are not likely fail any sooner..
purples prioritize writes so you dont drop frames on recording, and have power management, queueing, and other specific firmware optimizations designed for video use.. unless you got alot of cameras you will be unlikely to tangibly see any of these benefits.
these HGST Deskstars are better than WD Reds, and Reds are great.. the 7200rpm spindle speed is quite noticeable, especially in a raid when speeds start compounding.
The problem is the green economy/efficiency lines, those have aggressive power management and constant surveillance use is far too abusive.