Just trying to wrap my head around this and looking some clarification.

Credit Substitution Guidance for v4.1.pdf (usgbc.org) indicates that one is allowed to register a project under v4.0 or v4.1 (we registered under v4.0), but can elect to substitute credits from v4.1 as desired.  It is my interpretation that the Minimum energy performance and optimize energy performance pre-req and credit must be substituted to the v4.1 standard.  Because otherwise, who would elect to do this over v4.0 ever? Why not just stick to requirements of v4 instead of trying to meet all of v4.1. What would the reasoning be and what are the advantages of doing so?