J.G.
I swaddled all 4 of mine, and the one I swaddled the longest actually crawled & walked the earliest!!
1st, swaddled for 6 months, crawled at 7 months, walked at 10
2nd, swaddled for 4 months, crawled at 10 months, walked at 13
3rd, swaddled for 3 months, crawled at 9 months, walked at 12
4th, swaddled for 3 months, about to crawl (she's 8 months)
I swaddled all of mine for naps as well as at night.
Hope this helps!