Why cannot user SharePoint Farm Account for application pool ?

As i understand if application pool account using the SharePoint Farm Account  is over privilege but today i just notice we can extract the service account password from the application pool .

with the following script then we can get the password then just understand using the SharePoint Farm Service Account for application is very risky for the security leaking.

 PowerShell

try{

Import-Module WebAdministration

Get-WebApplication

$webapps = Get-WebApplication

$list = @()

foreach ($webapp in get-childitem IIS:\AppPools\)

{

$name = "IIS:\AppPools\" + $webapp.name

$item = @{}

$item.WebAppName = $webapp.name

$item.Version = (Get-ItemProperty $name managedRuntimeVersion).Value

$item.State = (Get-WebAppPoolState -Name $webapp.name).Value

$item.UserIdentityType = $webapp.processModel.identityType

$item.Username = $webapp.processModel.userName

$item.Password = $webapp.processModel.password

$obj = New-Object PSObject -Property $item

$list += $obj

}

$list | Format-Table -a -Property "WebAppName", "Version", "State", "UserIdentityType", "Username", "Password"

}catch

{

$ExceptionMessage = "Error in Line: " + $_.Exception.Line + ". " + $_.Exception.GetType().FullName + ": " + $_.Exception.Message + " Stacktrace: " + $_.Exception.StackTrace

$ExceptionMessage

}

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