In theory, I'm a passive rear advocate for cruise intervals.
In practice, if I'm doing the workout on the track, I adhere to the passive rest approach. If I do it on the roads, I jog because standing around on a sidewalk 5 miles from my house just seems goofy.
The theory behind my advocacy for passive rest is that the goal of the workout is to allow your body to adapt to the presence of waste products and to learn to better clear those waste products at pace. Since jogging, and even walking, clears those waste products fairly effectively and quickly, there is a slight dminishment in he return you get on the workout when you have active recovery.
Ultimately, I think we are probably talking about fractions of a percentage point on the rate of return, and that all assumes that the underlying physiology is right in the first place. So I wouldn't get too worked up about it either way - as evidenced by my mixed approach.