We used it only for nighttime, and found, through our own bleary-eyed research, that our girls would calm immediately once they were swaddled, and stay asleep longer. It was actually nice for me because as early as Frannie's first weeks of life, swaddling became a "daddy thing". I kind of helped cement that status with one of those "You swaddle her so much better than I do. Can you please do it?" moves which guaranteed that I would rarely have to do the bedtime routine alone.
At the time, I never considered that there would be any adverse health affects from being swaddled for a few hours a day. I'm totally on board with the pediatrician quoted in the article who asserts that "Swaddling has been shown to increase 'quiet sleep' and sleep duration. It can help babies become accustomed to sleeping on their backs, which decreased the risk of SIDS." (Babies should not be placed to sleep on their tummies, especially when swaddled, which I would think is obvious but you never know.)
In this article I learned that there are viewpoints opposing swaddling as well, as a pediatric physiotherapist was quoted as saying that "swaddling can be interpreted as a form of restraint" and that it comes with worries about chest pressure which can affect breathing, hip dysplasia, and overheating.
We never wrapped the girls so tightly that they could not turn their heads to the side if spitting up (another concern) but we certainly tried to tuck the arms in (so they wouldn't fling them and startle themselves awake) which I guess wasn't advisable either, because then they couldn't put their hands in their mouths for self-soothing.
I am hardly one to argue when faced with hard research data or official health warnings, but at this point I would still highly recommend the swaddle for anyone who a) wants their child to stay asleep longer and b) is comfortable having their baby swaddled, which is obviously the most important point. If, as a parent, something doesn't feel right to you, then don't do it.
How about you? Were/are you a baby swaddler? Did you see benefits? Do these warnings change your thinking?