[my bolding]There's a few like that in the remote Highlands which were originally built for large hunting estates - I would imagine what little traffic they do get is still nearly all leisure orientated but now is towards walkers rather than hunters.
Corrour, with 12,630 passengers recorded in 2019/20* (and more in each of the two previous years), is actually one of the busier intermediate stations on the West Highland. Presumably this is to do with the popularity of hill-walking and the fact that it gives access to a large area which is hard to reach by other rmeans.
*ORR figures as reported by Wikipedia.
(I think its original function included being a passing place for trains, rather than purely a private estate station, but as it's no longer normally used as a passing place either, it still fits the thread).