Well it depends on exactly what you use it for.
XML files are human readable, which means that you can easily see their contents
It is a standard format that can be read by almost any modern coding language/platform, making the files easy to share and use in other applications.
It is easy to perform basic validation of XML files providing a schema has been defined.
The are a lot of tools/technologies associated with XML, such as XSL:T which can do things useful things like change files from one schema to another.
That said, there are some situations where it might not be suitable, e.g. large volumes of data. It cannot replace a database in most situations.
XML files are human readable, which means that you can easily see their contents
It is a standard format that can be read by almost any modern coding language/platform, making the files easy to share and use in other applications.
It is easy to perform basic validation of XML files providing a schema has been defined.
The are a lot of tools/technologies associated with XML, such as XSL:T which can do things useful things like change files from one schema to another.
That said, there are some situations where it might not be suitable, e.g. large volumes of data. It cannot replace a database in most situations.