Someone works in the ER
When I think of sealing a wound I think about two areas. First, the outer margin of the wound is live bark layers, and sealing them will keep them from drying out and may hasten the rate with which they callous over. Second, the inner part of the wound is (in most cases) deadwood. Sealing it does nothing for the tree, per se, but what it may do is keep water and fungi out, preventing the deadwood from rotting.
In this case, the bandage serves neither purpose well.