For any user data entry is very combersome  task and many times users have to fill same data in few fields for different record  . To avoid the repetition, User Default  is very handy solution which allow user to save the personalize  data per enitity in his configuration and which can be easily loaded in next record as desired 
Following are the key advantages of the solutions :
a.) It can reduce the repetition time and save the user’s time
b.) It can help cloning data basis user specific details
c.) It can increase the accuracy of the data