TB I would say it was Michael's effort to make it APPEAR the family was completely legitimate. He still "owned" politicians, he acquired Moe Green's Casino and Klingman's casino by moving them both out (the first one without Roth's permission, the second one with it), he controlled Pentageli's New York operation, he committed perjury before congress, and of course he killed all his "enemies" at the end of the movie.