I'm new to the concept -- can you clarify something for me? Looking at AAPL, which is priced similarly to your example, if I sell the just OTM put and buy the next farther OTM put, which is a bull credit spread, I see I'm positive 11 delta. So I short 11 AAPL. Now I'm delta neutral, and from the spread itself, pretty close to neutral on gamma, vega and theta. But when I look at the macro PnL diagram, it sure looks like I've taken a short position in AAPL. I guess I'm "locally" delta neutral, but what advantage did I gain? My risk just went to infinity on the upside, when with the spread I was at full profit there. I was bullish with the spread, now I'm overall bearish.
I guess the answer is that I shouldn't neutralize delta when I have a directional view on the underlying? What exactly are the situations that lead one to trade this way -- you are seemingly making your hay with vega, but what leads you to that strategy?