Wow, good post, thanks for sharing!
I'm not sure one-way links would be useful for a learning type brain, at least I can't think of any. I've found them useful when I only want to see the items linked when on a specific topic, and when from the context of viewing the thoughts themselves the child/jump thoughts would just clutter it up.
For example, I have a thought that shows all Access databases that I use. However, the databases themselves are linked to other areas, and I only need to see the list of Access databases when on that specific thought, not when I'm accessing the database thought from it's usual location. (I hope this makes a bit of sense
In practice, I've found it a bit hit or miss whether it actually displays the linked thought or not when on the one way linked thought, which is a bit annoying. Hopefully they are still working on ironing it out a bit.