QGIS » QGIS Application

If such a simple piece of script as this answer http://gis.stackexchange.com/questions/103863/how-can-values-in-the-attribute-table-be-refreshed-automatically-when-a-geometry/190416#190416 can make fields update automatically, why on earth is this not just the default action of the software? I can't think of a single case scenario where one might change the outline of a polygon but want the associated database to still store the old area value, it certainly can't be a common requirement. I know virtual fields now do this, but as has been discussed, you can't do any further work on them, they're not seen by many plugins and can't be carried over into other software. I've put this as a feature request, but I'd also appreciate any insight into why the default position is not to have fields automatically update when it seems so simple to make them do so.