Currently, pressing the toggle causes the client to act as if RMB is being held down. However, in certain applications (e.g. bedrock breaking) this isn't fast enough. A better way would be to emulate the way the client acts if the use key is set to a physical key on the keyboard and held down; doing such results in a much higher click rate for actions like placing blocks, ringing bells, interacting with doors, etc. but retains normal behavior for, say, eating food.

Note that when holding the use key when it's bound to a physical keyboard, there seems to be a short "warm-up" period (observable with doors) where the clicking happens at a normal rate, then accelerates. If possible, skipping this warm-up period would be good.