I guess a question would be what is the intent? Assuming exchange 2007 or 2010 in a small single server environment to make the self-signed certificate errors go away when accessing OWA?
If you drop a single name cert on exchange for that and the internal name does not match the external name (servername.ADdomain.local vs mail.publicdomain.com) then OWA will have a nice happy matching SSL cert but now when outlook 2007 or newer connect to the server it will generate an error on the client side. If you put in a UCC cert you can have the cert be valid for both the public and private names.
As much as godaddy can bite my ass, we have yet to find a UCC cert provider that is anywhere near the same ballpark for pricing on a UCC cert. In most cases, the above is the ONLY reason for the existence of the SSL cert at all so $60/yr vs ~$250/yr is a tough sell for a small business.