I will go with first the required rollercoaster passion. You're sacrificing your life for 6-8 years of building. And at least five years of rollercoaster ride.
Vision matters, and how that ties in to potential token value too. But a lot will change along the road as well. Remember that Instagram was initially a full-blown social network but the users used only the photo filters (no wonder in that era our mobile cameras were crap). AirBnB was about airbeds, yes. Uber was a luxury limo rental.
Most startups will pivot two to three times. A white paper and BC, while more strict upon first thought, also offer much lenience to chance model. The core vision needs to have "spunk" but will eventually be only a minor part of the mainstreamed product.