What is a disadvantage of a stand-alone installation versus a distributed installation?

What is a disadvantage of a stand-alone installation versus a distributed installation?

A.
You are forced to use Windows as operating system.

B.
Clientless VPN would not work in a stand-alone installation.

C.
The SmartCenter Server must be a secondary server. You are forced to install a separate primary server.

D.
You must use a central license.

E.
You cannot install software packages on a Security Gateway via SmartUpdate.