This method, when used appropriately, may be useful for some children who do not have "severe" attachment issues. Children with secure attachments who have normal "acting out" behaviors will probably not be adversely effected by forced holds, and may show some signs of benefits (though I question whether those same benefits would not be achieved by minimized physical contact while coaching a child in expressing their emotions through words). I strongly advocate against this method for children with anxious or avoidant attachment patterns--as do most other therapuetic professionals I work with (I, personally, am not a professional--but an adult who has worked through the challenges of anxious/avoidant attachment styles).
From my experiences and the numerous reports of others in similar circumstances, I have come to believe that forced holdings may appear to have short term benefits. After all, children with insecure attachment patterns are primed for survival, and if you must submit to forced holdings in order to survive you will quickly learn to do so. However, in the long run, forced holding has adverse effects on attachment and responsiveness to physical contact. Personally, after entering therapy of my own accord in college it took two years before I was able to willingly allow someone to hug me (though I still would submit to hugs in situations where it was "culturally appropriate"). Forced holding did nothing for my attachment patterns--though initially there may have been a decrease in negative externalized behaviors (followed by an increase in internalized behaviors such as self-injury and suicidal ideation).
On the other hand--using these methods for voluntary holds can work wonders, I use "holding time" as a voluntary activity for many of the emotionally challenged (and emotionally typical) children I work with. The benefits of voluntary and appropriate physical contact can not be emphasised enough.
For good guidelines on appropriate intervention techniques, try Dr. Becky Bailey's "Easy to Love, Difficult to Discipline" and "I Love You Rituals". The "I Love You" rituals alone are often enough for me, as a teacher, to break through with difficult children--and they are all presented in method that is voluntary, interactive, and nonthreatening--unlike forced holds.