Besides maintaining the status quo of kleptocracy, how else does religion in a practical sense serve society? Guns, Germs, and Steel chapter 14...

Because “kleptocracy” is not a term used much outside of
Guns, Germs, and Steel, and because that book discusses the ways in
which religion supports kleptocracy, I assume that your question is from Diamond’s
book.  I have edited and moved it accordingly.  If my assumption is correct, the answer
to your question can be found on p. 278 in the book.

On p.
278, Diamond says that there are two ways that religion can be of use to society, other
than simply helping to maintain the status quo of the kleptocracy.  First, religion
helps allow people who are not related to one another to live together in peace.  At the
beginning of Chapter 14, Diamond talks about how hard it is for unrelated people (and
people who have no personal ties) to live together without violence.  Religion reduces
this problem.  It gives people something that binds them together (they both have the
same religion) and therefore makes violence less likely.  Second, Diamond says, religion
gives people a reason to sacrifice themselves for the community as a whole.  They will
be more willing to die for their community in war if they believe that God (or the gods)
supports that community.  If religion makes people more willing to die for their
community, the community will be more powerful in military
terms.

These are the two reasons that Diamond gives for why
religion serves society other than by simply supporting the
kleptocracy.