I think bloodborne holds a lot of reverence because of the themes it portrays. Besides Sekiro, which also has a cult following, all the other Souls games are based in and around medieval fantasy of some sort.
Bloodborne starts in Victorian England with a Van Helsing story and the descends into Lovecraft really fast. For a lot of people, myself included, that’s inherently a more interesting setting than medieval fantasy. People who are into victorian England are really passionate about it, and people who are into Lovecraft are really into Lovecraft.
Alert.
It’s broken. The initiative die in BG3 is a d4, which makes the bonus from alert game-breakingly good.