The ZI SW is very much a specialty product, missing the parent model's viewfinder & rangefinder that are arguably the very best on the market. Too bad to give that up even if it were just so-so. You can do everything with the Zeiss Ikon that you can with the SW and much more... but of course at the cost difference between the two models. So cost is really the main benefit to the SW. And as suggested above there are other camera models used and new that could save a lot of $$ without sacrificing the RF, or in the case of the Bessa L or T save you even more.
The ZI SW is kinda cool in its own way, but any time I'm tempted by it I'm reminded that the ZI is way better for almost anything (and I already have one), and that the Voiglander Bessa T is way cheaper and also takes bayonet lenses but is missing auto exposure... and I already have one, and that the Bessa L is even more basic, limited to screw-mount lenses (and I already have one). So I pass on the SW, cool as it may be. 🙂