Bloodlines are a lengthy, but still sketchy, variant idea from Unearthed Arcana. Like everything else in that book, they don’t have the same level of detail and rigor that you expect from the usual rules. Like everything else in that book, it is a mistake to read very much into the RAW there, even if you generally find value in RAW.
And bloodlines are really messed up. They are not a good system. If you follow discussions of them, it seems like the only reason anyone cares about them is the possibility that maybe they can be abused for freebie bonuses. There are so many other, better ways to establish a flavorful “bloodline” heritage for your character, that there is just no real reason to deal with the massive headache that is bloodlines when all you want is flavor.
So really, my answer to the question is not only “who knows?” but also “who cares?” I mean, it’s a valid question, I don’t doubt that someone will probably take an interest in hashing through Unearthed Arcana’s suggestions and treating them as hard rules, but 1. I still think that’s a mistake, and 2. I don’t think there’s enough value in them to be worth the effort. Even if you get answers to your questions that you find convincing, the bloodlines rules will still be bad and still be something you should avoid including in your games.
Unearthed Arcana is a book of ideas. Not all of them panned out. Bloodlines is one of those.