Why don't NPCs use active Disciplines?

[Shizz]

Well.. the title says it all, I guess. Why don't they? Apart from a certain fire mage in a certain locked-down building, all they ever use are passive Disciplines like Celerity, Presence or Potence. Does anybody know why this is so?

[Lukeatus]

Well, I guess it'd be more difficult for the game developers. But a few more NPCs do use non-passive disciplines.
Examples:

*Spoilers*
-The Prince (dominate) if you try not to comply with his requests;
-The Sheriff if you go up the stairs;
-Some Lasombra at Hollowbrook;
-And a certain Flesh-eating bloodline (Does not belong to 13 clans) kindred.
[If you choose fight it]

It'd be cool if the Malk on Bloodhunt used such disciplines, it'd make the fight more difficult.