So much minutia to the game, I am still learning after owning for 6 months. Sigth and sigh Di and Tele (Tele is really useless other than Tanglevine etc...)
Teleport has many uses:
Get the opponent mage to the zone you want him to be in.
Escape creatures and getting rid of hindering with a QC before your activation phase.
Move a creature to the other side of a wall if the caster has vision to both sides of the wall (huginn or your mage if positioned correct).
Skip a trap you suspect to be a teleport trap.
Get out of quicksand (currently its the only garuenteed way).
Teleport slow creatures away from your side of the board making them spend several rounds getting back in the fight unless your opponenent chooses to spend actions and mana getting them back.
Teleport creatures with regen away from hindering enemies and make the creature take a few steps further away by itself.
Take that gorgon Archer out of tanglevine and put it in a better position where it can do its ranged attack.
etc etc.
With all the spellbooks i have made only one had 0 teleports... and thats because i was out of copies tbh.