The motor emergency switch is not for saving your day, it’s for saving someone else day or car or house. It you get any trouble so that machine is not manouverable you can choose to kill motors on a clean spot if possible and let it fall without risk of hurting someone. I would never fly bigger copters without motor emergency switch.
Thats exacly why I have e-stop switch!
Also if the copter does not disarm when landing, due to fail in landing detection its good to cut the motors with the switch.
BTW about No Pulses FS option, it depends on what protocol is used between receiver and FC