Use of column 'IsPreferredAccount' of table 'ADSAccount'


Can you please confirm about column 'IsPreferredAccount' of table 'ADSACCOUNT' is used in system.Currently this column 'IsPreferredAccount' value is set to 'False' for all user accounts in system by default .
Please help in answers for below question :
1. Where column 'IsPreferredAccount' is used by the system.
2. If i change the value of column 'IsPreferredAccount' to be set a 'true' for fully Managed account - What is the impact on system or UserAccount. Does system use this flag in some internal calculations? Please share details and confirm on same.