One point I have used is using an unsupported barrel causes the leads to be
clinched per 5.2.7.2 which costs more with the added labor. The main
reason I have found that customers choose unsupported barrels is to save a few
bucks on the PCB. The added labor reasoning normally gets most
customers to see the cost savings is really in using a supported barrel plus the
added bonus of the mechanical strength the barrel does give.
Kathy