Is Scry on Familiar an obvious waste of time?

I recently noticed that on top of getting a great level of spell resistance and inheriting their master’s excellent base will save bonus, a Wizard’s familiar grants the Scry on Familiar (Sp) ability to its master, with the benefit "If the master is 13th level or higher, he may scry on his familiar (as if casting the scrying spell) once per day". Is my mathematical intuition mistaken, or, even at level 13, will the familiar almost always block this, making it useless? It’s an SR: Yes spell and it is negated by will saves, both of which I suspect a Wizard’s familiar to be great at.