The traditional way to place silicone breast implants is manually, where the surgeon handles the implants with his surgical gloves. The disadvantage of this method is that the implants are slippery and the smaller the incision, the more handling of the implant it takes to get the implant in place.
Potentially, this creates skin to implant contact, which is not ideal since skin harbors bacterias, even after cleaning with cleansing agents prior to insertion. Also the handling of the implant may cause microtrauma to the implant that is not noticed and may diminish the useful age of the implant.
There is really no patient disadvantage that we can think of, in terms of the Keller Funnel. Of course there are costs to the Keller funnel, but these are not passed on to the patient since Dr. Khalifeh wants you to have the best possible outcome he can perform, and uses the Keller funnel in cases of primary breast silicone augmentation.