c - What is the purpose of returning a char* in strcat, strcopy, (etc), when there is a destination variable?

Just a silly but quick question: Why do some functions that work with c style strings such as: fgets, strcpy, strcat, etc, have a return type of char* when there is a variable in the parameter list that stores the output? ie, why is it:

char *strcat ( char *dest, const char *src );

and not

void strcat ( char *dest, const char *src );

or even just returning the result by doing

char *strcat (const char *src );

I mean I can see how this would be useful if you are nesting calls to these functions (which is dangerous) but I don't see why you need to have both a destination variable AND returnt he result...

I'm reviewing some c programming stuff and can't believe how much I forgot!

Answer

For the sake of ease of usage, so that these functions can be used in larger expressions or can be nested.

Something like:

strcat(path, strcpy(file, "foo.txt")); 

or

printf("[%s]\n", strcat(string1, string2));

Needless to say these usages can and should be avoided.