The labial frenulum often attaches to the center of the upper lip and between the upper two front teeth. This can cause a large gap and gum recession by pulling the gums off the bone. A labial frenectomy removes the labial frenulum. Orthodontic patients often have this procedure done to assist with closing a front tooth gap. When a denture patient’s lips move, the frenulum pulls and loosens the denture which can be uncomfortable. This surgery is often done to help dentures fit better.
The removal of the frenulum does not cause any adverse effects to the lip and mouth. The real question is if it has any beneficial effects.
“Potential” benefits include better feeding, diminished decay of the front incisors, and avoiding a central diastema (gap in the front teeth). I remain a bit skeptical that the benefits exist.