Hi!

Three main reasons:

1. It helps other users to assess the reliability of such places. This particular place was added 10 years ago, and such places are less reliable than the places added 1 year ago or less.

2. It simplifies re-verification, since starting with the oldest and most out-of-date places gives you more bang for a buck.

3. There is no automated way to figure out the date of the last meaningful edit, it requires manual assessment on a case by case basis (change set author, comments, tags affected, etc.)