There are ways to train reallistically and still stay safe.
You can train low heel kicks on kick shields or against somebody with heavy leg protection on like cricket leg pads , or those plastic baseball leg guards , they work pretty well.
Strikes to the throat and neck can be trained on the wooden dummy , on focus mitts or kick shields , or on the partner by slightly modifying the strike and hitting the upper chest or pulling back the strike.
Knee strikes to the groin and bladder have to be trained on kick shields , or slowly on a partner wearing groin protection.
Biu jee elbow strikes can be practiced full power on focus mitts , or kick shields , if doing them on a partners sternum it's a good idea for the partner to be wearing a chest protector and the striker to seriously limit the amount of power they use.
When targeting the back of the neck , commonsense applies and you pull back the elbow strike just short of contact.
Training this way with heavy gear on , is certainly not conducted all the time , but occasionally you have to low heel kick a persons leg for real , at full speed and full power and the only way to safely do that is with serious leg protection on.
One of the reasons that chi sau came about , is because it is a very safe way for Wing Chun people to spar.