Fimming is just topping.. you damage the node but leave enough ramining it can recover and grow out -- the healing can result in extra branches from that node plus the 2 axillary buds that normally form just below - auxins re-distribute growth temporarily to things that wouldn't normally have apical dominance after damging the plant just like topping. The difference is that the damage doesn't fully destroy or remove the top most growth node
It's inconsistent. You cannot predict the outcome, so it's a useless technique. More is not always better, anyway. It's better to have an end goal as far as number of colas per sq ft of space and work backward from that goal formulating a plan to reach it in a systematic and efficient way. A whimsical mass of branches is not ideal.
It's click bait or an epeen. It may make an individual feel like they accomplished something, but provides no real benefit and sometimes is a negative.
