One possibility is that for short duration, low to moderate load stretching - meaning that which we can do by stretching manually - intermittent pulling works better.
JAI stretches or DLD Blasters (the same thing) involve stretching for short periods. I’m only speculating, but this pulse approach may have benefits over longer duration static manual stretching for several reasons:
1) You pull harder. Yep. When doing “short duration” stretches you’ll pull harder than if you have to maintain that same degree of stretch for a long time.
2) Cyclical loading. I’m not sure about this, but it seems repetitive loading and unloading causes the tissues to be stressed more with subsequent applications of the same load.
Otherwise, longer-duration is the way to go, and hanging is required for that. Try using your hand to exert exactly x lbs. of downward force on your dick for an hour. You can’t. Even if you manage to do it for a day, your hand and arm will be so exhausted you won’t be able to do it the next, let alone every day.
When/if you try hanging in lieu of manual stretching, you may be quite surprised at how much more the tissues are stressed with increased time under tension. I doubt I can gain now from stretching by hand. I’m certainly not willing to work myself into a sweat trying. Hanging works.