For me, it's still very much a serious observing tool. A highly regarded one, even. I primarily use mine as a solar telescope and a quick-look grab and go instrument. You can get adapters, so you can use modern 1.25" eyepieces on it or even 2", to some degree (the version with the internal focuser can be fully adapted to 2", but the version with the helical focuser can not, due to lack of sufficient back focus).
The old 0.965" Zeiss eyepieces are extremely sharp and contrasty, but I still recommend getting adapters so you can use modern 1.25" eyepieces. The optics in most Telementors is superb and will show crisp, sharp views.
My Zeiss Telemator with 1.25" Baader prism, Quark H-alpha filter and Baader binoviewer.
Observing the Sun via a Zeiss solar projection screen and good, old-fashioned solar projection method. Very nice for group viewing and instruction.
How to attach a Baader Maxbright or Mark V binoviewer to a Zeiss Telementor/Telemator
How to attach 2" eyepieces to a Baader T2 diagonal on the Zeiss Telementor/Telemator. NB! Some clipping of the outer field will occur with eyepieces with large fieldstops, but it will reach focus with all Telementors.
If you have a Telementor 2 or a Telemator and can get a Baader Maxbright diagonal with SC-threads, you can adopt it to your Telementor 2 or Telemator, for true 2" capability. There will be some dimming of the outer field in large eyepieces, but the apparent field will not be reduced.
How it appears in real life.