Why use xml over ini files

I have just began a new project and have decided to use XML or XLS files to store project data instead of INI files.Should I stay with *.ini or should  I change?? Which type should I use?? what is the difference between XML and XLS
when I read and write to an Ini file  I use the following code.what do I use for XML or XLS?


Option Explicit

Declare Function GetPrivateProfileString Lib "kernel32" Alias "GetPrivateProfileStringA" (ByVal lpApplicationName As String, ByVal lpKeyName As Any, ByVal lpDefault As String, ByVal lpReturnedString As String, ByVal nSize As Long, ByVal lpFileName As String) As Long
Declare Function WritePrivateProfileString Lib "kernel32" Alias "WritePrivateProfileStringA" (ByVal lpApplicationName As String, ByVal lpKeyName As Any, ByVal lpstring As Any, ByVal lpFileName As String) As Long

Public Function WriteIniInfo(FileName As String, AppName As String, KeyName As String, StringName As String)
Dim x As Boolean
    x = WritePrivateProfileString(AppName, KeyName, StringName, FileName)
End Function

Public Function GetIniInfo(FileName As String, AppName As String, KeyName As String)
Dim A As String
Dim i As String
 A$ = Space$(255)
     i = GetPrivateProfileString(AppName, KeyName, "", A$, 300, FileName)
      GetIniInfo = Left$(A$, i)
End Function