Hey,
Such a list is off course easier to maintain, but offers limit possibilities.
Data like the amount of players, the status of the game, the different servers, ranking of the players, direct linking to OpenID authentication etc. are impossible to keep up to date in a regular list.
And I know developers are lazy people, but it's really not that big of a deal to upload an XML.
The advanced features are not required.
The coolest features of this list is, to me, the "instant play" feature of OpenID, allowing players to start playing the game straight away, without registering.
So, yes, it requires some effort. But the return is rather big.