Like Lancer, Saber has protection against projectile weapons.
Lancer reads the course of the projectile attack using the sound of cutting air and the enemy's murderous intent.
Saber uses the sound of cutting air and her own instincts.
"Imperceivable attacks" are not much of a threat against heroic spirits.
It is those attacks that cannot be blocked, even when detected and understood, that are the fatal ones.
In that regard, Lancer's lance is appropriate to be called a Noble Phantasm.
A weapon that always strikes the heart cannot be blocked merely by knowing about it.
If one is to oppose that demonic lance, one must…
Prepare a shield overwhelming the magical energy of the lance,
have great enough luck to change the fate determined by the lance,
or prevent him from using the lance in the first place.
Compared to that, Assassin's daggers are easy to manage.
They can be fatal if they strike any vital points, but they are no different from throwing stones.