To change the permanent location in the item can lead to incorrect results. If you have two holdings with different locations and then change the location of the item which is connected to the first holding to the location of the second holding, your item will be relinked to the second holding AND the first holding will be deleted automatically. If the first holding contained additional information (e.g. the call number), this information will be lost.
The option to change the permanent location in the item should therefore not be a default, it should be selectable depending on the needs of the institution. Some may find it useful, others not.