How come every date seems to use the medium format? What’s the point of the other formats, if that’s the case? And how can I use a different format for different display instances, e.g. comments and articles? I can theme-override the dates, but I’d be happier (and it would be better for the clients) if I could get that customisation just with the UI settings.
I’ve never changed the date format (short, med, long) in regular content except to change the way it’s set up mm/dd/yyyy or dd/mm/yyy, etc… I have found it very useful to mess about with the date formats in my views though and that’s where I think they are probably must useful.
As I mentioned above, I can—and do—theme-override dates with no great difficulty (and simpler than the code at your URL). I just wondered (1) why the three date formats exist when Drupal seems only to use one of them for everything; and (2) why there is apparently no option anywhere to pick a date format for each content type. Which is a totally dumb omission.
I expect the reason they have 3 formats is so that you can take advantage of them with customizing. ie: modules or theming. As I mentioned earlier, I sue this often with views when I add a date field to a content type and then create views for that content.