I mean in real life, it is also a chaos. Say Delta Airlines DL129 Seattle-Beijing. They do get confused sometimes as well, especially when the traffic in PEK is very busy. When they are confused by meters, the tower just instead tell them descend to FL250.
Also, it is a good idea to make it hard, and you as the controller in expert server can ghost more users. In another request, people say the rules in expert server aren’t strict enough. Metric and imperial unit conversion is a good way to kick some of the not-fully-trained pilots back to the training server.