It's a nice little feature for sure but totally overkill for large solar system fuses that are easily checked and will probably never blow a main fuse.
Looks like I'm late to the game and a lot has already been covered.
Personally I've never connected a cable here. In the RV's I've worked on, the positive cable feeding to the coach fuse panel is the same slot I put the negative cable going to the frame. If I had to use it, I probably would get the ring on top of my lug even if it meant taking the screws that hold the PCB out. I get that Victron wants it used only in case of a ground fault, but then you have the whole RV/mobile world that uses the frame as a negative connection - there could be quite a few amps going across the frame (think generator starting, slide outs/hydraulic leveling pumps).