Yes it does , and it attracts deer , and maybe caribou too
But once the plant freezes, it becomes poisionous to deer , and the seed shatters .
But you plow it under before it flowers. It does not produce seed that way and the soil gets the benefit of the under ground composting of the cover crop.
I suppose you'd have to be extra diligent to get all the plants. Plus in planting, some seed doesn't germinate but will in a following year.
Clover is good but I got some nasty stuff in compost, never saw white clover like that. Sprouted all over where I'd applied the compost. Had to use a weed killer to get rid of it.
I liked the idea that the buckwheat smothers weeds. I read a little more on that site. A combination of other plants, about 3, can't remember which ones except I think buckwheat was one, are allotropic. They work like Neem and inhibit germination of seed so you have to wait about 3 weeks to plant over what you had.