Of course it would be suitable for stereo photogaphy, optimal distance to subject (for natural 3D feel) would be x30 the separation between the centers of the two lenses, so around 3 or 4 meters, the 1/30 rule...
The optimal film format perhaps was larger than 4x5. It could be 5x7 or 8x10, seller does not mention the separation between the glasses. It looks to me that the separation would be better for a 8x10 back, resulting two 8x5" images. If glasses (axis) were separated 5" then this arrangement would be perfect for a 8x10 sheet in the back as each lens axis would nail the center of each of the two images taking each the half of the sheet. If that separation is 3.5" then it would be intended for 5x7" sheets in the back, for a two 3.5 x 7" images.
Of course it also would be good to assemble a TLR accessory in the back, with a roll film back catching the image from a lens and a reflex ocular catching the image of the other lens, but as lenses are horizontally arranged (see lettering direction) then it was intended for stereo. If the lenses were arranged vertically (one ove the other) then than device would probably be for a TLR usage.
Well, with that gadget one can DIY both a TLR or an Stereo device, perfect for both, but IMO it makes more sense for Stereo. Still no shutter is seen, so it looks it was not intended originally for general photography, also it not looks constructed for aerial usage, perhaps it was used in the industrial or scientific realms.