Since provider fails to verify with XRDS-Simple, what do I lose without it?

I installed the this OpenID plugin and XRDS-Simple on my server, then used the ruby-openid tool to test it out. It seemed to work partially, but it gave me the following error in the UI:

Verification failed: No matching endpoint found after discovering

(These error messages may not help you since this isn’t the ruby-openid forum, but there’s always a chance.) Here are the error messages I get from the consumer logic, in case it helps:

Error attempting to use stored discovery information: OpenID::TypeURIMismatch
Attempting discovery to verify endpoint
Performing discovery on https://www.sinksolvers.com/office/?author=1
WARNING: making https request to https://www.sinksolvers.com/office/?author=1 without verifying server certificate; no CA path was specified.
WARNING: making https request to https://www.sinksolvers.com/office/?xrds without verifying server certificate; no CA path was specified.
Discovery verification failure for https://www.sinksolvers.com/office/?author=1
 * Endpoint mismatch: OpenID::TypeURIMismatch

I finally found a trick that let the whole thing work after reading the last comment on
this thread.

Sure enough, after disabling XRDS-Simple it worked like a charm.

The error may be of interest for finding a bug in this plugin… but my question is: what do I lose by disabling XRDS-Simple?

Thanks for a most excellent, useful plugin!

http://wordpress.org/plugins/openid/