See Neelesh's comment here: Enable Automatic Login / Trusted Authentication & SAML in 8.1
The answer is yes, SAML really is usable for single sign on in embedding Tableau BI inside your application.
Using trusted tickets, Tableau is trusting the web app hosting the embedded viz that the user is already authenticated *by that app*. Using SAML, the IdP authenticates the user separate from the web app hosting the embedded viz. If your web app hosting the embedded viz supports SAML and you have an IdP, or feel the need for one, use SAML. If you simply need the app and Tableau to work together and there is no larger need for SSO (via SAML) across other systems, use Trusted Authentication.