When the bank phone rep asks "Is this charge to 'fat-flirt.com' yours?", it is definitely nice to be able to say "No, it
is not".
On the negative side, over the last month my wife has managed to have both our primary credit card and her debit card compromised (ok, I am not entirely sure it is her fault but circumstantial evidence points in that direction) so I am thinking of putting her on the "Cash in envelopes" system.