We used certs because we did not want to have to worry about managing passwords in source code, or in config files, etc. By using certs, our development team did not have to concern themselves with this stuff, and I think it made it easier for us to address the compliance auditors.
If you don't mind managing the passwords, then I believe what you've described is all there is to it.
PS - This is an older article, relevant only to SQL 2005. I believe this has changed quite a bit (for the better) in SQL 2008.