Consider natural twisted convoluted Junipers as example. Such did not happen by regimented formulaic pruning. In whacking off all bottom branches possible natural future movement is removed along with better personality/less wire for tree
. Personally have found such branches(or twigs)of great value several times
. When bending time is correct consider small twigs/branches value for future and begin bending at early stage when easy to do. At same time consider if wanting bigger trunk to be developing sacrifice growth. Also do not consider any Bonsai pot if wanting to grow bigger trunk but instead growing box or ground.