I don’t know about that. Dynamic Swings, PNF and static stretches (only at training, they rarely do their given homework) have worked wonders for my clients.
Just doing Static does very little for Bad tightness, but works for short term tightness, esp right after a workout. Oh, everybody in my group always does Dynamic movement Before sessions. These two, static and dynamic work good for 80% of the people. The others Need PNF - and a lot of the times its just to teach the hip flexors to actually Work from yrs of inactivity or stubborn tightness.
You get Faster results when coupled with massage etc, But considering the area involved, not many like being massaged there!! Foam Rolling is KING in that spot, so too the groin.
The maths does add up if you do at least 2 of the 3 stretches, and at times, all 3. The trick is actually doing them. And foam rolling, And checking out all the other muscles that affect the hips area. Most are too lazy and don’t do it.