The last update to 0.8 before the unstable 0.9 builds started being released added these. If you light them up and go to a specific place, you'll get a new plushie. The wiki has a guide on how to do it if you want specifics.
Idk there are so many plushies in the game as is, it would just be disappointing if another secret led to one. The whole thing with the shack leading to a lambert plushie still makes me frustrated, you need to get 4 special runes that don't even work 100% of the time through various complicated means, take all of them to a specific part of the map at 3:33 A.M, and then stab yourself with the ritual knife. It just seems like so much effort for something so relatively tame. I get the game is still in active development and everything, i would just like if these secrets led to lore instead. But hey, that's just me.