Gymnasts, martial artists, ballet dancers and some athlets (e.g. javelin throwers) stretch to increase their range of motion because the latter is beneficial for their activities. The effect is temporary (+) unless you start at a young age and ruin your joints (-> China). If you don't belong to those groups, stretching doesn't do much for you, as has been repeatedly pointed out in various publications. The other benefits attributed to stretching, e.g. a lower risk for injuries, are actually caused by the warming-up effect of the stretching movements and can be also achieved, in a much safer way!, by some simple exercises.

(Side note: When talking about the benefits of stretching, some people also mention Yoga, but that's a different story and 99.999% of Yoga teachers and practitioner don't have the slightest idea what they are doing.)

(+) That's the reason why you have the impression that you are stiff when you skip stretching for one or two days.

Try squatting deep without being flexible. Squatting --> strength --> better posture, metabolism, & bone density.

That article seems to aim at the hype that stretching will help with anything other than stretching. It's pretty obvious to anyone who ever tried that practice helps you stretch farther, but some people also stretch because they believe it will prevent injury or make their muscles more efficient or something like that.

I stretch because it feels good. I don’t expect a cure from cancer for it, though.