Things are more uniform and constant this way. If too little pressure is applied or the stone is too low on the mast, the result will be a rounding towards the heel of the facet closest to the mast. Varying hand pressure will result in rounding in all directions. You will unknowingly exert varied and probably excessive hand pressures when you are tired, unhappy about something, or feeling the effects of your martini. So work on your competition stone when the time is right.
Tec machine does have one.
In my opinion, other faceting machine features like a larger angle gauge attachment, electronic gadgets, or an attached microscope are useless for serious competition cutting. The coarser laps required to get rid of most of the rough are used to speed the work, The coarser laps are all extremely uneven and not considered with this Stop Method. This whole procedure is done only with the fine cutting and polishing laps. If you find that the stone just touches your moving lap in all areas equally, then you have a very flat lap and your machine is perfectly aligned. But there are always tolerances involved.