He didn't have Emery with him at Roma. Emery's going to know everything he needs to know about a player and how he would fit into his plans before he approves a signing. Presumably Emery and Monchi worked together at Sevilla.
Whoever heads up the recruitment department will do all the leg work before Emery reviews it. As long as it's Emery taking the decisions, the DoF then can do the work of bringing them in. I don't think it's a problem.