Absolutely wouldn’t buy a Nerd for just the compass. But I might decide I want one in the future. I have some buddies who have them and hopefully I’d be able to borrow one to see how I like it.Which is smart, fixed cables are pretty stupid IMO.
But I wouldn't buy a NERD for a compass alone, because I can count the number of times I used a compass outside of a class exercise in one hand, and probably have fingers to spare. In cave diving from what I understand they are only primarily for surveys. And those compasses are more like a map compass so you can align it with the survey line.