Well longer-term may mean weeks instead of the short time frame here. For example many stocks hit lows in their IVs in the trough between earnings- GOOG is great example. So you get in at a point like that and then perhaps in two weeks sell the straddle as long as IV gains outweigh theta.
Quote from riskarb:
Yeah, not a bad idea to replicate vols in such a way, but you'll be long vega and short gamma based if trading equal positions. I can't tell you exposures as I don't know your idea of "longer term" -- just an idea, but I would err to trading similar term-structures.
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