I find the All Change field interesting but can't figure how it is useful.
The Latest Changes feature allows you to review all of the changes users make to an ancestor’s record in Family Tree. You can then reverse the change if you feel it is incorrect or contact the person who made it. In some circumstances, you have to click Reference to see the restore option.
It is usually a good idea to reach out to the other user since—like you—he or she likely feels a strong attachment to the ancestor. Perhaps you can work together to achieve a fuller, richer account of your ancestor than you would if you work by yourself!
If you want to see who made changes to a particular Life Event, go to Vitals: Event and click Edit. You are able to see who made the most recent change.