Spirit Pacts - What's to gain ?, Some pacts are unclear Options

[PatB]

Please help. I'm failling to understand the various spirit pacts as described on page 108 in Street Magic or their gain versus their cost. Note that a Spirit Pact costs, at character creation, the spirit's edge pool times 5 BP, or time 10 Karma:

Drain Pact: The mage can use the spirit's Edge pool for any magic-related resistance test. Very addictive and the spirit may ask karma. That one is fine and is in fact dangerous, probably too much for a player to take it.

Dream Pact: The spirit has control over the bounded character when he sleeps. The spirit gains karma through its action. However, what does the bounded character gains in return, especially if he doesn't remember anything "he did" ?? Worse is that the character suffers any impact of the spirit's actions.

Formula Pact: Gain Immunity to Age and the spirit's formula. Fine with this one, but I'm not convinced it's worth the cost in BP/Karma, unless the character doesn't have to do an astral quest to get the formula ?!?!

Life Pact: Exchange 1 Karma to heal 2 physical boxes. That's a life saver for those dire situations. Fine with this one too. Actually, it's probably the one that makes more sense to me.

Magic Pact: Once per day, enhance Magic attribute by half the spirit's magic attribute for Force combat turn. The spirit may use the character's Edge without asking. Seems fine, except that you need to deal with the use of Edge

Power Pact: The mage can use one power from the spirit, and the spirit can use one spell from the mage. Lasts 24H. Not sure why a spirit would go this way ... or why a mage would refuse such a deal ... unless both the mage and spirit can't use the power/spell it gave ??


Any thoughts ?? Did any of you used the Spirit Pacts ??
Thanks