It's knowlege, pure raw information, and experience. It's deceptively evil, not like ZOMFG with spikes, and blood dripping from it, but more subtle than that. In essence, knowlege is Power, and of the two types that seek it, the Scholars who do so for it's own sake, like Septimus Signis, or Ulrag are fairly powerless against the Warlords, who want a fast track to 80 perks, daedric armor of invulnerability, and godslayer sword.
It's like The Ring, (you know the One) it doesn't look That bad, in fact it kind of pretty, but that's the deception. A lot of people think it's just a ring of Invisibility, because the little people who used it really wanted to not be seen. (And it backfired horribly) Instead, it was the one to rule it all, the Kings that became the Nazgul to take over the world, and rule by right of Magic. That's why Hobbits are the designated bearers, they're so powerless, it can corrupt them (like a Riverfolk named Smeagle) but not make them a threat. Anyone else would become essentially an 11th Nazgul (Boromir) Psychopathic Berserker (Legolas, Gimly) or corrupted black wizard, (Sarumon, Galadriel, or even Gandalf, who would likely be worse than Sauron himslef.) But the hobbits have friends, the fellowship to protect, and guide them.
The Dovakiin already has unstoppable power to beat down the World Eater. Give him Infinite knowlege, and I guess he could be benevolent, but just look at all the level 81 builds, including ones with names like "Utopia." And besides, you really think this:
Wants to just give it to you, no strings attached, out of the goodness of it's heart? (Assuming it has one, instead of a squeedily spooch.) Yeah, he really looks trustworthy. Ever wonder why it doesn't appear to you face to, uh, whatever?