It is vastly easier to manage and strongly secure that single point, for administrators, security professionals and users.
You can enforce a much higher security credential, as it only has to be used once. You don't have to worry that your users are re-using the same weaker credential across multiple independent services (hint: they will).
Using SSO does not mean you have no defence in depth. You should always consider defence in depth in the context of the overall system. It's not a strong reason IMHO against centralising or simplifying one type of control.
It is vastly easier to manage and strongly secure that single point, for administrators, security professionals and users.
You can enforce a much higher security credential, as it only has to be used once. You don't have to worry that your users are re-using the same weaker credential across multiple independent services (hint: they will).
Using SSO does not mean you have no defence in depth. You should always consider defence in depth in the context of the overall system. It's not a strong reason IMHO against centralising or simplifying one type of control.