Some stepper drivers can detect when a motor has stalled an can then send a signal to the mcu so it can take some action. That action could be an emergency stop which would allow the work and bits to be saved. Some new 3D printer designs are using stall detection to eliminate the need for limit switches. My CNC router has recently developed a infrequent one second stall on the x axis. This results in a shift in the x direction which can cause the bit to plow into the work and destroy the work, the bit, or both.
No need for stall detection on a properly built machine. That stall could be Wiring: docs:blackbox-x32:faq-identify-motor-coils [OpenBuilds Documentation] - particularly a loose connection that intermittently looses contact, or incorrect Max Rate and/or Acceleration settings:
