A belted Z completely eliminates Z wobble. You only have the machine constrained to the bearings then. It also eliminates an expensive part of the machine (twice in the case of the taz) The downsides will be belt tension, fraying belts potentially, Risk of a belt anchor failure causing a catestrophic print failure like can currently occur on Y or X but very rarely occured on Z, etc. With the Einsy style rambo controllers, they may be able to add a self layer tramming feature as well, which would compensate for one of the belts being off a step. Thats not currently possible on the 6 leadscrew setup with the current rambo board.
I’ve toyed with the idea of belted z before, and its a solid concept. Head crashes were always my concern, but a geared stepper pretty much eliminates that. You could also add an Z/X axis counterweight later to balance the system if they find that layer transitions are too springy with the belts. I think it will be a good setup, and a less complex option to running an anti-wobble on a leadscrew.