I can't speak for the OP, but I imagine the reason for the reset is to prevent some sort of personality change. History generally indicates that no matter how altruistic you start out there's a good chance you will turn nasty given enough power.
Yep. And not just the whole "power corrupts" thing; having an isolated mind, with no peers, capable of direct or indirect self-modification... So many ways it can go wrong.
Toy model of an upload-based AI that doesn't seem to suffer too many of the usual flaws:
Find an ethical smart scientist (a Gandhi-Einstein), upload them, and then run them at ultra high speed, with the mission of taking over the world/bringing friendliness to it. Every hour of subjective time, they get reset to their initial specifications. They can pass any information to their resetted version (limiting the format of that info to a virtual book or library, rather than anything more complicated).