After reading the caveats you may be wondering how SSL can help anyway. Actually there are some really good uses for SSL. Intraorganizational is by far the greatest and best use of SSL email security that I can think of. SSL email can easily protect intraorganizational communications such as corporate, educational, government, military, healthcare, etc... This is especially important where confidentiality/privacy concerns are high, in fact recent privacy laws and legislation such as HIPAA may require that certain email communications be encrypted.
SSL works well in these environments because all of the communication systems can be placed under the central, internal control of the organization. Intraorganizational mail can be handled by one or more servers which all support SSL. The servers may be setup to require all incoming connections to be encrypted with SSL, and all mail clients can very easily be configured to connect to their company server via SSL. This is a fairly easy situation to implement and administer and will provide excellent email security within the organization. Communications between Employees, Executives, Board Members, Contractors, those on the road and those working from home are all easily protected by a very high level of security.