I'm surprised by the strength of your comment. The article doesn't argue for lowercasing everything, and cites several cases (ah!) where it shouldn't hurt. Including case insensitive languages where case doesn't carry any information by definition and where it's already common practice and uncontroversial to lowercase everything, and English title case. With this in mind, my next question is:
> they greatly enhance readability
Do you have any evidence for this? My native language is not English and we use the Latin alphabet. The case for titles is the same as for regular sentences. We are doing fine. I would even say that the English title case feels somewhat odd and confusing. Titles are also virtually always set apart / rendered differently as normal text so I fail to see how normal case for titles loses information and how title case helps in any way. Actually, I even believe that title case sometimes loses information. Capital letters mark (Mark, btw :-)) proper names, this marking is lost with title case and this may sometimes bring ambiguity.
> they greatly enhance readability
Do you have any evidence for this? My native language is not English and we use the Latin alphabet. The case for titles is the same as for regular sentences. We are doing fine. I would even say that the English title case feels somewhat odd and confusing. Titles are also virtually always set apart / rendered differently as normal text so I fail to see how normal case for titles loses information and how title case helps in any way. Actually, I even believe that title case sometimes loses information. Capital letters mark (Mark, btw :-)) proper names, this marking is lost with title case and this may sometimes bring ambiguity.