You're not missing anything, but there are a lot of people here who find community to be more important than tribe or biome. As for names, I mean, we're the ones who will be running the world, why should we be tied solely to the names of our eventual tribe? I want a name that represents me and my character, not only the tribe I am a part of. Also, as it currently stands, kings and dukes will be able to reserve half the spots available in their domains for lower nobility, so many these alliances that are forming now are more or less concrete.
With heraldry, some people just move quickly and want something to represent them until we are provided with the means to create one.