Limited future sight seems like a great ability to have, just like you said -- enough foresight to enrich oneself but not too much that you worry about all the negative events in the future.
If you could see into the future and adjust actions to change the course of events, it would change the future, but also the course of events, meaning that what did you actually see? Are you the instigator of change, or a product of it? Was it you, or destiny?
This is really the crux of the issue though... if we can see the future and can take action to change it, did we really see the future or just one of myriad possible futures available to us. Is this person seeing the future, or just the current future based on life at that exact time? If more than one person can see the future and they have different incentives, they could both be actively working to change the future in different ways. That would render the future they see as inaccurate, or maybe their vision updates and changes in real time.
Too many possibilities... maybe I will just go back to believing in God heheheh