The trading-relevant skill is not calm; it is noticing. A trader who registers the impulse to click before clicking has a choice that a trader who only notices afterwards does not.
Practice is separate from performance. Ten minutes daily away from the screen builds the noticing habit; trying to meditate during a drawdown does not. What transfers to the desk is a short check-in - what am I feeling, what do I want to do, what does the plan say - repeated until it is automatic.
The claims should stay modest. It will not improve your read of a chart or your edge. It improves the odds that you follow your own rules, which is usually where the money is.
Related: affect-labelling, emotional-regulation, self-talk, tilt-protocol