I can't speak for this particular lupine species, but in Europe lupine seems to be a good candidate in the search for a native plant species that can be grown here instead of soy beans. Personally I don't really like the taste of soy products so I hope that works out. And it's a nitrogen fixer too, which is a nice bonus.
For example, I have seen various lupine tempe brands, and in Germany I can get lupine "coffee" (it's not quite the same but tasty on its own terms, and I need to avoid caffeine).
The varieties that are made into tempeh and similar products are specifically bred for that use, as I understand it. Wild lupine beans in general are mildly/moderately toxic. The same thing that gives them the bitter taste is dangerous in large quantities, so they have to be prepared carefully to reduce it.
However it is a very beautiful plant and the flowers are good for insects like butterflies!
The varieties of blue lupine (Lupinus angustifolius) that have become popular here in Sweden are low in the bitter toxic alkaloids and don't require the cumbersome preparation. Protein content is at ~36% and I find them very tasty.
It should not be confused with another blueish colored lupine that came here from North America and is considered one of the most problematic invasive species. Lupinus polyphyllus.
For example, I have seen various lupine tempe brands, and in Germany I can get lupine "coffee" (it's not quite the same but tasty on its own terms, and I need to avoid caffeine).