Please excuse my response in English...
Yes, I think you are describing correctly, the edges of this watch are so thin that a larger-diameter movement would be not in proportion. Also, as the individual wheels and other moving parts are very thin, making them larger individually would cause them to become unstable, whereas this movement is designed to be functional, rugged and accurate, so it is sized to fit the thickness as well as the case.
If you do not mind links to English reviews, these writers are much more expert than I:
https://www.timezone.com/