Yeah it’s not very clear in the video. To use the laser, you modify GRBL parameters 30,31,32, 10, and use G10 L2 P1 to set different work offsets.
In his video, the “use laser” macro does:
$32=1
$10=0
G10 L2 P1 X- Y-<valeur_max>
while the “use CNC” macro restores values to:
$32=0
$10=255
G10 L2 P1 X0Y0
so you can see that params 30 and 31 are left unaffected by the “use CNC” macro. Which is why he takes a shortcut and tells you to rerun the “send shapeoko config” in Carbide Motion, while that is not really necessary: 30 and 31 happen to be the min and max RPM, used by the Shapeoko controller to adjust the PWM signal: if you have a router on your shapeoko, the PWM is unused, so it’s not a problem that 30 and 31 have been modified, and you can perfectly use Carbide Motion without setting the config again, as long as you ran the “Use CNC” macro in Lightburn before exiting (to restore $32/$10)
Note: if you have a spindle though, then you do need to restore 30 and 31 to their original values (in my case 0 and 24000) before using the CNC again.
EDIT: i checked the end of his video and he does mention that using Carbide Motion to “send config” is only a shorter/simpler way to reset the GRBL params than doing the $30/$31 params modification manually.