For birds nest I take the cutters and tap the branches I need to prune. Coral tissue is designed to sheer off in break scenarios (like a rock falling on them or storm action) Vs a straight line like cutters. Breaking off speeds up the healing process because of the specialized cells corals have are designed to break off in zagged edges leaving whole cells untouched and will have an irregular tissue edge vs straight line. This keeps sections of cells undamaged and full of their fluids and nutrients. This speeds up attachment as these cells are designed to reattach quickly as they don't have to heal first then attach. They typically are sticky speeding up the bonding to the rock process. Plus sometimes cutters are unwieldy in a tank and you risk hitting other corals with the handle. Sometimes you do have to use cutters if the branches are dense and thick and depending on species and growth form cutters work best. Something like a tabling acro where the calcium core is thick and dense and hard to break except for the growing tips will usually need cutters to cut the main coral body. Corals like birds nest that are branching easily break off. If you have a specific portion you need to cut off, say a side that is touching another coral or you are going for a specific frag or shape you might need to use cutters. As the tap option you don't know where it will break off. I have even used the tap option on LPS like frog spawn, elegance or open brain. For coral shapes like open brain or elegance you can smack them breaking the skeleton allowing the tissue to remain attached to the majority of the skeleton. This allows the coral to release the tissue on its own pace and heal the other portions.