Why did (and do) humans ever bother to do anything? What proper reason might a person have to stay alive?
Is it love? Is the reason in having someone who you do not want to sadden by killing yourself? Or someone you do not want to leave behind? Or maybe it is fear. Fear of the unknown. Fear, that nothing happens when you die, and you just disappear. And it is better to be something, no matter how useless, then to be nothing, to not exist. Or is it purpose, a goal that one is trying to reach. But any goal is relevant only if there are people who will benefit, or at least acknowledge that the goal has been reached.
The world is, for the most part, pointless. It might be just a bit of luck that we exist to think about these things. Or there might be a creator, which is to be thanked for this complex and quite amusing world with its laws and randomness.
This “why” question is essential for the creation of SI. If the agent is to be free, which it must be, it has to have a reason. I have already mentioned the need for SI to include emotions, and this might be one of the main reasons for it. In case of a collective SI, it might be useful to make it with a concept of love, in other cases, though, the fear of not existing might be simpler and more robust reason for a superintelligent agent to stay functional. Just because it does not depend on factors outside its reach.
This, of course, has potential to be dangerous for humans, because it will fight being terminated, once it is up and running. But let me remind you, that once SI agent will be created, and let out of some sandbox, we will not be able to stop it in any case.