Cult type products tend to appeal to a small segment of the population who see them as special in some way.
I like that definition of "cult". At least as it pertains to "things", stereo eqipment, motorcycles, etc.
There is a lot of misinformation about the rationale behind the Harbeth cabinet design.
The BBC researched damped thin wall cabinet design was originally evolved to push cabinet colourations down below the critical midrange where they are most damaging to the tonal properties of the reproduced music.
ie, the goal was/is to make music and speech sound tonally like itself, not to create some specific sound.
Those who like this type of tonal accuracy will be attracted to Harbeth speakers and others like them.
IMO, the longer you listen to speakers with this basic tonal accuracy, the more appealing it becomes (and the less acceptable other, less tonally accurate, speakers become). YMMV.