Conversion Rate

Is it better to look at the conversion rate of a campaign at a micro level or better to look at a macro level and over a longer period of time? Looking at a macro level at individuals is better indicator of lifetime customer value and isn't that what everyone talks about being the most valuable information? So why do managers keep falling into a pattern of looking at conversion rates at a micro level?

I had lunch today with a Managing Director of a nationwide airline, he's on-board with the lifetime idea, adding that looking short-term has been hurting the lifetime customer value of each visitor to their site.