> The tube provides immediately a visible record which can be kept on in detail at leisure. This record can, of course, be traced on paper or photographed with a simple camera. (…) For most of the applications it was found that direct observations were sufficient.
[0] https://www.cdvandt.org/Blauschrift-Roehre.pdf
Wikipedia includes a passage on rapid film recording and development as an alternative (based on fluorescent CRTs):
> Even the use in radar was not widespread; looking for an even larger format system with better properties, the RAF turned to the Photographic Display Unit, a system that took a photograph of the display, rapidly processed it, and then projected it through a modified movie projector. Even with this complexity, it was faster than the skiatrons, producing a new image every 15 seconds] while the skiatron units were typically longer due to the erasure process.
[1] https://en.wikipedia.org/wiki/Skiatron
(Note: provided the short clip in that film, I cannot see how the argument really adds up. I guess, the log and analysis aspect was important. Moreover, I assume, as the size of the projection exceeds what is possible with direct projection and you have to opt for intermediate steps anyway, "conventional" CRTs were preferable for any photographic process because of their contrast properties.)
For more on the Photographic Display Unit, see: