I don't think the gap is huge by any means. But I think you've hit the nail on the head with identifying Giroux as the better option. I would see the difference being not much more than a depth player. An exception would be in a limited keeper league where it would make sense to difference would be bigger if one was trying to improve their keepers.
Ultimate Dynasty League
16 Team Dynasty League H2H: G, A, P, PPP, SHP, +/-, PIM, SOG, W, L, GAA, SvPct, SHO
C: Stamkos, Getzlaf, Carter
LW: Ovechkin, Kovalchuk, Brown
RW: Iginla, Pavelski, Horton
D: Byfuglien, J.Johnson, Goligoski, Hedman, Hamonic
G: Schneider, Hiller,
B: E. Johnson, S.Kostitsyn, Neil, Biron, Giguere
Prospect: Nail Yakupov, Tangradi
UHL Dynasty St. Louis Blues
...a bad team trying to rebuild...