Why is '@' allowed before any member variable (i.e. call to a function/Property) when it doesn't affects its value?

I know '@' keyword is used for different purposes in C# as discussed here, but my question is different.

Suppose I am using @ConfigurationManager.AppSetting["DbConnectionString"] in place of ConfigurationManager.AppSetting["DbConnectionString"]. It still works in the same way.

So my questions are:

1. Why is the '@' symbol allowed by the compiler here when it does not affect its value?
2. Can the '@' symbol change the values in any scenario as mentioned above?

To make it more clear I want to add one more Example:

Suppose, I have a class 'ConfigurationLoader' that has a static function 'GetConfigurations' returns a list of strings.

Then,I can call it as List<string> ConnectionStrs=ConfigurationLoader.GetConfigurations();.

If I make it as List<string> ConnectionStrs=@ConfigurationLoader.GetConfigurations(); then it still gives the same result. In such senario, I am asking above two questions.