Dimir Control leans on Counterspell, Snuff Out, Cast Down, and Agony Warp, so protecting our key threats and permanents matters a lot. Tamiyo's Safekeeping grants hexproof and indestructible, dodging their removal suite and Counterspell-adjacent disruption entirely on a resolved permanent, while gaining 2 life to help us race Ninja of the Deep Hours and Thorn of the Black Rose. Red Elemental Blast and Blue Elemental Blast have no place coming in from our side since we don't have them in our sideboard pool relevant here, and we skip any artifact hate since their only artifacts are creatures. We trim the slower looting/sacrifice pieces (Bitter Reunion, Melded Moxite) that do little against a grindy control deck that will simply remove or counter them.