Yes, exactly. Every species I am growing in this project has edible and tasty nuts.. I think every pine tree actually has edible nuts.. but some are so small and taste bad. But from what I have read the ones I picked are pretty good in size and taste.
It is a cool material. Yes, the roots will grow out of the cube and you just plant the cube along with the rooted plant. Eventually the rockwool will break down.
I haven't really eaten pine nuts before, but I remember reading somewhere that they are one of the more expensive varieties because they are difficult to harvest and process (though I can't recall the details clearly).