The reason are perhaps because of the movement, the case, or the line it self I guess... They are rare for a reason, but in not a good way I think...

I think because it's quartz, and the size...?

While this kind of straight lug is pretty rare by itself...

And this one

Because it uses 625 movement? Or due to its size that's small in today's standard?

Or this cool looking seiko

One way it was quartz and it's not as fancy as their KS or actus or their divers...
Well... HAGWE Everyone!
Best
Jev