They're very neat but if you think about why they were ever made at all its a bit more clear. I think a lot of these are 30s-50s style infomercials. One of my favorites explains how a differential works[1] but its more clearly a Chrysler commercial. Presumably this Disney clip was entertaining enough to have been part of a tv show but could have also been some promotional material.

These days we only get this stuff in recruiting material or SAAS ads.

[1] https://www.youtube.com/watch?v=yYAw79386WI