The advantage is, it can check whether you have entered the password correctly or not just by clicking on the eye icon on the left of the password field. The disadvantage is others can easily see the password by clicking on the eye symbol which is a password reveal option. The password reveal option is shown in every password entry field as shown below.
We can Enable / Disable this feature in windows8.
#1 Open Run Prompt ( Win+R )
#2 Type gpedit.msc
#3 Local Group policy editor will be opened as shown below
#4 In Computer Configuration Expand Administrative Templates–>Windows Components–>Credential User Interface
#5 Open Do not display the password reveal button and click on Enabled option.
#6 Now We have Disabled the password reveal option. We cant see the eye icon on left side of the password field.
To Enable the Option Just follow the above steps and select Disabled option in Step 5 as shown above.
Note : To Disable the feature we have to click on enable and for enabling we have to click on disable because the group policy editor is converse.(opposite).