Why is it needed? Ive only repaired a few dryers, but this looks like extra part. This dryer has the std High-Limit Thermostat, Operating Thermostat, and Thermal Fuse. However, it also has this Thermal Cut-Off Fuse. This Thermal Cut-Off fuse is located in the heater housing where it feeds the drum and looks more like a thermostat. Its also the most expensive part.
See attached diagram. ( https://imgur.com/a/Q3vVHeP
#1 Thermal Cut-Off Fuse
#34 High-Limit Thermostat
#42 Operating Thermostat
#59 Thermal Fuse