i think its fine for occasional usage (and i can definitely see why they do it, when to do things chronologically would result in a very boring cold-opener), but yeah - overusing it makes it lose all its impact and effect.
It's normally used as lame misdirection hook. Something like seeing a main character killed in the first 5 minutes then rewind to early in the day/month/year and see how it's 'shock horror' all a setup and they aren't really dead afterall!
I don't mind it too much - I'm currently raging at 10mins of every 40min program being filled with "last time" and "coming up" segments, occasionally reminding me of what happened only minutes ago in case the ad break and my trip to the kitchen for a brew somehow induce amnesia.