You don't need to actually use it against a military target. You just need to demonstrate you are ready and willing to use it.
A warning shot. It is a psychological weapon.
And it's particularly effective if it is delivered in a means that could not be intercepted, and also when one did not have a warning was going to happen. So you make sure it is delivered hypersonically, and you make sure the fact that it is going to happen is compartmentalized so tight that no western "ears" realize it is happening until it has happened.
Imagine what it would do to the American military if we suddenly had to be at Defcon 2 for a long time? Not only is it expensive, it is actually scary for those D.C. pencil pushers who know it is going on, and have family that is near a potential target.
Russia may decide it needs a cuban missile crisis pressure on the United States. The CIA folks who had to go home every night, knowing about those satellite photos, and couldn't even tell their wives -- well, that kind of stress may just be what Russia wants to have happen in this instance, to pressure NATO to back off.