"SQLServerMSSQLUser$ComputerName$InstanceName" account do not create by default

After installing SQL EXPRESS 2014 "SQLServerMSSQLUser$ComputerName$InstanceName" account in Local Groups of Window 7-64BIT do not create by default.

But installing SQL EXPRESS 2008 "SQLServerMSSQLUser$ComputerName$InstanceName" account in Local Groups of Window 7-64BIT is created.

I want know the reason why do not create this account?

Have the account replace this account?

refer image: ComputerName = 317QuangTT6, InstanceName = SQLEXPRESS