I agree it should do something, which might be configurable by the end user and implementation dependent. For example, a browser might have an option to display the time converted into your preferred time format and time zone. If the operating system environment has some way to specify that some text refers to date/time and can be used with other software in this way, then it would be possible to do that, too.

(My own Scorpion document format is intended to include this capability, as well as the ability to specify other things (e.g. units of measurement, international telephone numbers, how a word is pronounced, languages, etc) to be handled in similar ways, but it is not currently fully defined.)