would it be usefull to spend perk points in the magic trees like destruction, alteration, ect. for playing as a vampire. also would it have any effect on the vampire lords spells like making them stronger or costing less mana?

Good question. I believe that it does help your vampire lord powers indeed. But I am not sure, there isn′t much information about this as far as I know.

It won't change the vampire lord at all. The only perk tree that changes the campire lord is his/her own. Just like werewolves.