[Rd] backtick notation

[Gabor Grothendieck]

Could someone explain the thinking behind the backtick notation in 
r-devel?

I think I understand that it can be used to refer to variable names
which would otherwise not conform to R syntax; however, assign and
as.name already allow you to do this.  Is there more to it than that?

Is backtick notation supposed to be analogous to backticks in the 
UNIX shell, the $ sign in perl or some feature in lisp/scheme?