Allowing simple footer customisation in settings?
In Drupal 6, the Site information settings page at /admin/settings/site-information has a "Footer Information" field that meets your description above.  If this field is not empty, and you do a major upgrade of your D6 site to D7, then your footer information will be moved into a block called "Footer message".  While it would be possible to re-implement the "Footer Information" field from D6 in D7 with a custom module, or in the settings for your theme (which would be even easier) I think it is clear that D7 designers felt that using a block for this purpose was the best and most general solution.