I know that sometimes beguile doesn't work for certain reasons, but it should do what it said on the card. At the very least, KI should explain when and how beguile works, because it is a waste of pips when I don't know how or when to use it.
Beguile is used to force the opponent to cast the spell on their team, or other NPC they are sided with.
Using beguile can be tricky because you need to be a mind reader and know when they are planning to use an attack spell. Because they can cast wards and charms that will consume the beguile spell. Just what a death wizard wants, a +25 to their next fire spell. * shakes head* Because this happens so much to me, I never seem to be able to time it correctly. It is like you say, a waste of pips to me.
But they are amazing when you can get them to work. Especially in PvP teams. In order to help work, you must understand each wizard school and it spells, and look for how many pips the opponent has, and when the best time to cast beguile would pay off.
If you hunt around this website and wizard101central.com, you can find hints.
Some pretty well accepted ones are
- it doesn't work against bosses - you need more than one opponent - if you go first, it works well in PvP
Some debatable ones are - you have to go first in PvE - it only works on Celestia and above. - you can use it on a bosses minion.
Someone prodded me into trying Beguile in Celestia, and I tried it, and it worked. Its like the monster is on your team, and your group attacks don't hit them either. Rebirth also heals them and puts that shield on them.
I have also noticed that if the mob is all of the same school, they naturally resist the attack, the exception being Balance and they cast Hydra.
In my opinion, for PvE, do it for a laugh against mixed school mobs.