In theory, yes.  Early in refinement hydrogen atoms tend to just make phenix.refine much slower.  Later in refinement, they can help with geometry and R-factors.  Personally I've never seen much benefit from using hydrogens at moderate resolution, but it's worth trying them and seeing what happens.  It's more important to pick optimal restraint weights (use the automatic weight optimization for this) and a good refinement strategy (add TLS, turn off real-space), and deal with any notable difference density peaks.

-Nat