I'm not an expert on the system and information on it is scarce, but I know the lens positions adjust. I've seen excerpts from reports with pilots using these saying that the pilots were able to land in the dark using them successfully. From that usage, I'd expect they have some success as pure visual aid devices and not just for range finding

My completely personal theory is that the technology of the time required the image intensification tubes to be so long. The design then allows the tubes to be pushed into an up position mimicking the human eye spacing though with a view coming from the top of the head. Probably took some getting used to.