When you are considering the Innerwear, we are talking about passive extension around the clock... even during sleep. There is also the convenience factor, in that there is no need to remove the Innerwear to urinate or have erections. Another consideration, it is made of 100% cotton fabric which effectively wicks away moisture so that the skin can breathe as it is designed to do. Silicone sleeves trap moisture which limits the duration of use for proper hygiene with the warm moist conditions being ideal for bacterial and fungal growth. With respect to PE, passive extension 24/7 helps cement gains made during the more active and dynamic training sessions.
The Innerwear is not to be relied upon as your one and only means to penis enlargement. Practitioners should explore a variety of exercises, devices, schedules, intensities etc in order to develop a routine that suits the goals, commitment level and lifestyle of the individual, with the deliberate intension to maximize efficiency. This is only possible with education, experience and very careful attention to feedback from the body in the form of sensation and observation of both the anatomy and the mechanical nature of the devices in use to gain the most benefit.
Mastering the learning curve is both a science and very much an art.