The “provides service” feature, in combination with a URL gives us a lot of power when it comes to referencing external resources. This allows us to change the nature of properties as the Wiki evolves. We can, for example, begin with a free text (or enumerated) list of country codes and, as some later date, change the “inCountry” property to be a URL with code substituted in the appropriate place. Something that would be really useful would be the ability to change the type to “Page” and, using a similar substitution mechanism, say something like “[[Country_$1]]”. Other use cases may include assigning a namespace as well, such as “[[:Category:Country_$1]]” or a in interwiki reference – “[[mw:Country_$1]]”. While we can simulate this with the URL mechanism, we lose all the advantages of the Semantic portion, as the referenced entity isn’t aware that we are pointing at it.
If other folks thought that this was a reasonable idea, we would be happy to roll up our sleeves and attempt to “make it so”, but we don’t want to spend a lot of time on a feature that won’t make it into the main development thread.