need for singleton Config ?

[Ravi Bansal]

Hi,

I was going through one of struts 1.2 reference , where its mentioend that configuration information should be stored in singleton config object rather than deployment descriptors or properties.
Reason for not using deployment descriptor is that

the values in the deployment descriptor are not visible from other business objects?

I did not get this . As ServletContext is accessibe from struts action object as well as other JSPs.
Can anyone tel me if there is really a need for using a singleton config object to store the configuration information.?