I understand your skepticism, but I'm coming from years of actual testing on many real-world devices that people use everyday and have no agency in upgrading for various reasons.
As I mentioned in other comments, there are many possible areas where HTTPS can present a barrier to a user's access to your resource. Some of these I listed in another comment, which I copy below:
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Only a few of the barriers presented by HTTPS:
Clock sync would be a requirement for access.
A recent device would be a requirement for access (not everyone can afford a new one).
Site admin keeping up with certificate registration would be a requirement.
Approval from the centralized certificate authority would be a requirement.
Server's self domain name matching accessed domain name would be a requirement.
These are all real scenarios where real people can be denied access to information that is crucial to them, up to the point of survival.
Just a few of the reasons why all my websites still allow HTTP.
