All bloodlines have a differing level of rarity based on how easy they are to breed, the total population of the bloodline
performance trait of the bloodline.
Nakamoto — Very Rare
Szabo — Rare
Finney — Not So Rare
Buterin — Common
The rarer a bloodline is, the more valuable it will be in the marketplace. Because it has a higher chance of winning or performing well in a race and has a higher chance of breeding stronger offspring. You can check the image above for reference.