I do it mostly because I’m working with material or designs that were done in Imperial, but when it comes time to setting up the machining I’m used to using metric because my other CNC machine has software that only supports metric. So I have learnt what feeds and speeds work best for my projects in metric.
All of my designs have been done in Imperial so I need to ensure that the machining matches what was designed. I do this all the time in my 3D CAD software was well as in my vector drawing software.
It just seems that it does not need to be that complicated by having to go to Setup to make the change. Why not have it more accessible it is not going to hurt anything to make life easier for those of us that want to switch back and forth.