Too secret is too confusing, and still too random. There's already quite a bit of randomness involved in Valheim, but it's offset by abundance and largely consisting of generic resources like iron, cores and whatnot. Combining unique persistent bonus with random discovery wouldn't be great.

Originally posted by Snow ☯:

Harvest extra berries and mushrooms because you harvested over 75 different things on the ground.

And these things are just filler grind, especially if built on top of the existing skill system and other progression farming.