I am pretty sure a head-on intercept is an “easy” target solution (for vastly complex mathematics involved in a target solution). Sharp maneuvers and even the slightest amount of damage would cause it to break up.
Gets a lot harder if your are the Aegis destroyer trying to protect a carrier, though.
The primary advantage would be reaction time. Ships can only guide limited number missiles at a time. By the time one missile goes into terminal homing against these monsters, you won’t have a chance to engage the next. So, if your ship can guild eight missiles, and they launch nine...
I was thinking of the US using them.
Head on intercept would assume the SAM was near the target.
If not it wouldn’t be a head on intercept.
If these things were fired from a couple hundred miles out there probably wouldn’t be time for a SAM to get on a head-on track.
High altitude launch, sprint to target, then a fairly steep dive, maybe ballistic stage.